C. S. Lewis, the famous Anglican apologist, once wrote:

The very possibility of progress demands that there should be an unchanging element . . . the positive historical statements made by Christianity have the power . . . of receiving, without intrinsic change, the increasing complexity of meaning which increasing knowledge puts into them. (God in the Dock, Eerdmans, Grand Rapids, Michigan, 1970, 44-47)

The Catholic Church, in agreement with Lewis, defines doctrinal development as a growth of depth and clarity in the understanding of the truths of divine revelation. It is important to understand that the substantial or essential truths at the core of each doctrine remain unchanged. Only the subjective grasp of men increases. This increase is the result of the prayerful reflection of the Church, theological study and research (often occasioned by heretical challenges), practical experience, and the collective wisdom of the Church's bishops and popes, especially when joined in ecumenical councils.

Like many Christian doctrines, the idea of doctrinal development is based on much implicit or indirect scriptural evidence (that will be compiled below). Furthermore, doctrine clearly develops within Scripture ("progressive revelation"). Examples: doctrines of the afterlife, the Trinity, the Messiah (eventually revealed as God the Son), the Holy Spirit (Divine Person in the New Testament), the equality of Jews and Gentiles, bodily resurrection, sacrifice of lambs evolving into the sacrifice of Christ, the canon of Scripture itself, etc. The Divinity or Godhood of Christ was only finalized in 325, and the full doctrine of the Trinity in 381. The dogma of the Two Natures of Christ (God and Man) was proclaimed in 451. These decisions of ecumenical councils were made in response to challenging heresies.

Not a single doctrine emerges in the Bible complete with no further need of development. In general, whenever Scripture refers to the increasing knowledge and maturity of Christians and the Church, an idea very similar to doctrinal development is present. Holy Scripture, then, is in no way hostile to development. Although understanding increases, the essential elements of doctrines exist from the beginning. Today's Church shouldn't be expected to look like the primitive Church if it is a living, vibrant, spiritual organism. But even the early Church looks like a small "Catholic tree." It doesn't look like a Protestant "statue."

Matthew 5:17-18 Think not that I have come to abolish the law and the prophets; I have come not to abolish them but to fulfil them. [18] For truly, I say to you, till heaven and earth pass away, not an iota, not a dot, will pass from the law until all is accomplished.

Matthew 9:16-17 And no one puts a piece of unshrunk cloth on an old garment, for the patch tears away from the garment, and a worse tear is made. [17] Neither is new wine put into old wineskins; if it is, the skins burst, and the wine is spilled, and the skins are destroyed; but new wine is put into fresh wineskins, and so both are preserved. (cf. Mk 2:21-22; Lk 5:36-38)

Matthew 13:31-32 Another parable he put before them, saying, "The kingdom of heaven is like a grain of mustard seed which a man took and sowed in his field; [32] it is the smallest of all seeds, but when it has grown it is the greatest of shrubs and becomes a tree, so that the birds of the air come and make nests in its branches."

Mark 1:14-15 Now after John was arrested, Jesus came into Galilee, preaching the gospel of God, [15] and saying, "The time is fulfilled, and the kingdom of God is at hand; repent, and believe in the gospel."

Romans 3:31 Do we then overthrow the law by this faith? By no means! On the contrary, we uphold the law.

Romans 4:11 He received circumcision as a sign or seal of the righteousness which he had by faith while he was still uncircumcised. The purpose was to make him the father of all who believe without being circumcised and who thus have righteousness reckoned to them,

Galatians 3:23-25 Now before faith came, we were confined under the law, kept under restraint until faith should be revealed. [24] So that the law was our custodian until Christ came, that we might be justified by faith. [25] But now that faith has come, we are no longer under a custodian;

Galatians 4:1-4 I mean that the heir, as long as he is a child, is no better than a slave, though he is the owner of all the estate; [2] but he is under guardians and trustees until the date set by the father. [3] So with us; when we were children, we were slaves to the elemental spirits of the universe. [4] But when the time had fully come, God sent forth his Son, . . .

Ephesians 1:9-10 For he has made known to us in all wisdom and insight the mystery of his will, according to his purpose which he set forth in Christ [10] as a plan for the fulness of time, to unite all things in him, things in heaven and things on earth.

Ephesians 4:13-14 until we all attain to the unity of the faith and of the knowledge of the Son of God, to mature manhood, to the measure of the stature of the fulness of Christ; [14] so that we may no longer be children, tossed to and fro and carried about with every wind of doctrine, by the cunning of men, by their craftiness in deceitful wiles.

Colossians 2:16-17 Therefore let no one pass judgment on you in questions of food and drink or with regard to a festival or a new moon or a sabbath. [17] These are only a shadow of what is to come; but the substance belongs to Christ.

Hebrews 10:1 For since the law has but a shadow of the good things to come instead of the true form of these realities, it can never, by the same sacrifices which are continually offered year after year, make perfect those who draw near.

Secrets, or Mysteries, or (Developed) "New" Teachings Revealed

Deuteronomy 29:29 The secret things belong to the LORD our God; but the things that are revealed belong to us and to our children for ever, that we may do all the words of this law.

Isaiah 42:9 "Behold, the former things have come to pass, and new things I now declare; before they spring forth I tell you of them."

Isaiah 43:19 Behold, I am doing a new thing; now it springs forth, do you not perceive it? . . .

Isaiah 48:6 ". . . From this time forth I make you hear new things, hidden things which you have not known."

Jeremiah 31:31-34 Behold, the days are coming, says the LORD, when I will make a new covenant with the house of Israel and the house of Judah, [32] not like the covenant which I made with their fathers when I took them by the hand to bring them out of the land of Egypt, my covenant which they broke, though I was their husband, says the LORD. [33] But this is the covenant which I will make with the house of Israel after those days, says the LORD: I will put my law within them, and I will write it upon their hearts; and I will be their God, and they shall be my people. [34] And no longer shall each man teach his neighbor and each his brother, saying, 'Know the LORD,' for they shall all know me, from the least of them to the greatest, says the LORD; for I will forgive their iniquity, and I will remember their sin no more. (cf. Ezek 11:19; 18:31; 36:26: "new spirit" / "new heart")

Jeremiah 33:3 Call to me and I will answer you, and will tell you great and hidden things which you have not known. . . .

Daniel 2:21-22, 28 He changes times and seasons; he removes kings and sets up kings; he gives wisdom to the wise and knowledge to those who have understanding; [22] he reveals deep and mysterious things; he knows what is in the darkness, and the light dwells with him. . . . [28] . . . there is a God in heaven who reveals mysteries . . .

Amos 3:7 Surely the Lord GOD does nothing, without revealing his secret to his servants the prophets.

Matthew 10:26 . . . nothing is covered that will not be revealed, or hidden that will not be known.

Matthew 11:25 At that time Jesus declared, "I thank thee, Father, Lord of heaven and earth, that thou hast hidden these things from the wise and understanding and revealed them to babes;" (cf. Lk 10:21)

Matthew 13:10-12 Then the disciples came and said to him, "Why do you speak to them in parables?" [11] And he answered them, "To you it has been given to know the secrets of the kingdom of heaven, but to them it has not been given. [12] For to him who has will more be given, and he will have abundance; but from him who has not, even what he has will be taken away.

Matthew 13:24-30, 35 Another parable he put before them, saying, "The kingdom of heaven may be compared to a man who sowed good seed in his field; [25] but while men were sleeping, his enemy came and sowed weeds among the wheat, and went away. [26] So when the plants came up and bore grain, then the weeds appeared also. [27] And the servants of the householder came and said to him, 'Sir, did you not sow good seed in your field? How then has it weeds?' [28] He said to them, 'An enemy has done this.' The servants said to him, 'Then do you want us to go and gather them?'' [29] But he said, 'No; lest in gathering the weeds you root up the wheat along with them. [30] Let both grow together until the harvest; and at harvest time I will tell the reapers, Gather the weeds first and bind them in bundles to be burned, but gather the wheat into my barn.'" . . . [35] This was to fulfil what was spoken by the prophet: "I will open my mouth in parables, I will utter what has been hidden since the foundation of the world." (cf. Mk 4:30-32; Lk 8:10)

Matthew 13:52 And he said to them, "Therefore every scribe who has been trained for the kingdom of heaven is like a householder who brings out of his treasure what is new and what is old."

Mark 4:22 For there is nothing hid, except to be made manifest; nor is anything secret, except to come to light. (cf. Lk 8:17; 12:2)

John 13:34 A new commandment I give to you, that you love one another; even as I have loved you, that you also love one another.

Romans 3:21 But now the righteousness of God has been manifested apart from law, . . .

Romans 7:6 . . . we serve not under the old written code but in the new life of the Spirit.

Romans 16:25-26 Now to him who is able to strengthen you according to my gospel and the preaching of Jesus Christ, according to the revelation of the mystery which was kept secret for long ages [26] but is now disclosed and through the prophetic writings is made known to all nations, according to the command of the eternal God, to bring about the obedience of faith --

1 Corinthians 2:7-11 But we impart a secret and hidden wisdom of God, which God decreed before the ages for our glorification. [8] None of the rulers of this age understood this; for if they had, they would not have crucified the Lord of glory. [9] But, as it is written, "What no eye has seen, nor ear heard, nor the heart of man conceived, what God has prepared for those who love him," [10] God has revealed to us through the Spirit. For the Spirit searches everything, even the depths of God. [11] For what person knows a man's thoughts except the spirit of the man which is in him? So also no one comprehends the thoughts of God except the Spirit of God.

1 Corinthians 3:1-3 But I, brethren, could not address you as spiritual men, but as men of the flesh, as babes in Christ. [2] I fed you with milk, not solid food; for you were not ready for it; and even yet you are not ready, [3] for you are still of the flesh. . . .

1 Corinthians 4:5 Therefore do not pronounce judgment before the time, before the Lord comes, who will bring to light the things now hidden in darkness . . .

2 Corinthians 3:5-6 . . . God, [6] who has made us competent to be ministers of a new covenant, not in a written code but in the Spirit; for the written code kills, but the Spirit gives life.

Ephesians 3:1-11 For this reason I, Paul, a prisoner for Christ Jesus on behalf of you Gentiles -- [2] assuming that you have heard of the stewardship of God's grace that was given to me for you, [3] how the mystery was made known to me by revelation, as I have written briefly. [4] When you read this you can perceive my insight into the mystery of Christ, [5] which was not made known to the sons of men in other generations as it has now been revealed to his holy apostles and prophets by the Spirit; [6] that is, how the Gentiles are fellow heirs, members of the same body, and partakers of the promise in Christ Jesus through the gospel. [7] Of this gospel I was made a minister according to the gift of God's grace which was given me by the working of his power. [8] To me, though I am the very least of all the saints, this grace was given, to preach to the Gentiles the unsearchable riches of Christ, [9] and to make all men see what is the plan of the mystery hidden for ages in God who created all things; [10] that through the church the manifold wisdom of God might now be made known to the principalities and powers in the heavenly places. [11] This was according to the eternal purpose which he has realized in Christ Jesus our Lord,

Colossians 1:25-28 . . . I became a minister according to the divine office which was given to me for you, to make the word of God fully known, [26] the mystery hidden for ages and generations but now made manifest to his saints. [27] To them God chose to make known how great among the Gentiles are the riches of the glory of this mystery, which is Christ in you, the hope of glory. [28] Him we proclaim, warning every man and teaching every man in all wisdom, that we may present every man mature in Christ.

Titus 1:2-3 in hope of eternal life which God, who never lies, promised ages ago [3] and at the proper time manifested in his word . . .

Hebrews 8:10, 13 This is the covenant that I will make with the house of Israel after those days, says the Lord: I will put my laws into their minds, and write them on their hearts, and I will be their God, and they shall be my people. . . . [13] In speaking of a new covenant he treats the first as obsolete. And what is becoming obsolete and growing old is ready to vanish away. (cf. 9:15; 12:24; Lk 22:20; 1 Cor 11:25; Jer 31:31-33 ["covenant"] )

1 Peter 1:5 . . . a salvation ready to be revealed in the last time.

1 John 2:7-8 Beloved, I am writing you no new commandment, but an old commandment which you had from the beginning; the old commandment is the word which you have heard. [8] Yet I am writing you a new commandment, which is true in him and in you, because the darkness is passing away and the true light is already shining.

Understanding, Knowledge, and Wisdom, Increased

Deuteronomy 29:4 but to this day the LORD has not given you a mind to understand, or eyes to see, or ears to hear.

Proverbs 1:5 the wise man also may hear and increase in learning, and the man of understanding acquire skill,

Proverbs 2:6 For the LORD gives wisdom; from his mouth come knowledge and understanding;

Jeremiah 3:15 And I will give you shepherds after my own heart, who will feed you with knowledge and understanding.

Jeremiah 23:20 The anger of the LORD will not turn back until he has executed and accomplished the intents of his mind. In the latter days you will understand it clearly. (cf. 30:24)

Daniel 12:4 But you, Daniel, shut up the words, and seal the book, until the time of the end. Many shall run to and fro, and knowledge shall increase.

Matthew 13:13-14 This is why I speak to them in parables, because seeing they do not see, and hearing they do not hear, nor do they understand. [14] With them indeed is fulfilled the prophecy of Isaiah which says: 'You shall indeed hear but never understand, and you shall indeed see but never perceive." (cf. Mk 4:11)

Matthew 13:19, 23 When any one hears the word of the kingdom and does not understand it, the evil one comes and snatches away what is sown in his heart; this is what was sown along the path. . . . [23] As for what was sown on good soil, this is he who hears the word and understands it; he indeed bears fruit, and yields, in one case a hundredfold, in another sixty, and in another thirty."

Luke 9:45 But they did not understand this saying, and it was concealed from them, that they should not perceive it

Luke 24:45 Then he opened their minds to understand the scriptures,

John 12:16 His disciples did not understand this at first; but when Jesus was glorified, then they remembered that this had been written of him and had been done to him.

John 13:7 Jesus answered him, "What I am doing you do not know now, but afterward you will understand."

1 Corinthians 2:12-14, 16 Now we have received not the spirit of the world, but the Spirit which is from God, that we might understand the gifts bestowed on us by God. [13] And we impart this in words not taught by human wisdom but taught by the Spirit, interpreting spiritual truths to those who possess the Spirit. [14] The unspiritual man does not receive the gifts of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned. . . . [16] "For who has known the mind of the Lord so as to instruct him?" But we have the mind of Christ.

1 Corinthians 13:9, 12 For our knowledge is imperfect and our prophecy is imperfect; . . . [12] For now we see in a mirror dimly, but then face to face. Now I know in part; then I shall understand fully, even as I have been fully understood.

Colossians 1:9-10 And so, from the day we heard of it, we have not ceased to pray for you, asking that you may be filled with the knowledge of his will in all spiritual wisdom and understanding, [10] to lead a life worthy of the Lord, fully pleasing to him, bearing fruit in every good work and increasing in the knowledge of God.

Colossians 2:2-3 that their hearts may be encouraged as they are knit together in love, to have all the riches of assured understanding and the knowledge of God's mystery, of Christ, [3] in whom are hid all the treasures of wisdom and knowledge.

2 Timothy 2:7 . . . the Lord will grant you understanding in everything.

Titus 1:1 Paul, a servant of God and an apostle of Jesus Christ, to further the faith of God's elect and their knowledge of the truth which accords with godliness,

Hebrews 5:11-14 About this we have much to say which is hard to explain, since you have become dull of hearing. [12] For though by this time you ought to be teachers, you need some one to teach you again the first principles of God's word. You need milk, not solid food; [13] for every one who lives on milk is unskilled in the word of righteousness, for he is a child. [14] But solid food is for the mature, for those who have their faculties trained by practice to distinguish good from evil.

2 Peter 3:15-18 And count the forbearance of our Lord as salvation. So also our beloved brother Paul wrote to you according to the wisdom given him, [16] speaking of this as he does in all his letters. There are some things in them hard to understand, which the ignorant and unstable twist to their own destruction, as they do the other scriptures. [17] You therefore, beloved, knowing this beforehand, beware lest you be carried away with the error of lawless men and lose your own stability. [18] But grow in the grace and knowledge of our Lord and Savior Jesus Christ. . . .

Guidance from God

Psalm 25:4-5 Make me to know thy ways, O LORD; teach me thy paths. [5] Lead me in thy truth, and teach me, . . .

Psalm 25:12-14 Who is the man that fears the LORD? Him will he instruct in the way that he should choose. [13] He himself shall abide in prosperity, and his children shall possess the land. [14] The friendship of the LORD is for those who fear him, and he makes known to them his covenant.

Psalm 86:11 Teach me thy way, O LORD, that I may walk in thy truth; . . .

Psalm 94:12 Blessed is the man whom thou dost chasten, O LORD, and whom thou dost teach out of thy law

Psalm 119:32-35 I will run in the way of thy commandments when thou enlargest my understanding! [33] Teach me, O LORD, the way of thy statutes; and I will keep it to the end. [34] Give me understanding, that I may keep thy law and observe it with my whole heart. [35] Lead me in the path of thy commandments,

for I delight in it.

Psalm 119:64 The earth, O LORD, is full of thy steadfast love; teach me thy statutes! (cf. 119:68)

Psalm 119:108 . . . teach me thy ordinances.

Isaiah 2:3 . . . "Come, let us go up to the mountain of the LORD, to the house of the God of Jacob; that he may teach us his ways . . ." (cf. Mic 4:2)

John 14:26 But the Counselor, the Holy Spirit, whom the Father will send in my name, he will teach you all things, and bring to your remembrance all that I have said to you.

John 16:13 When the Spirit of truth comes, he will guide you into all the truth; for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come.

Romans 11:33-34 O the depth of the riches and wisdom and knowledge of God! How unsearchable are his judgments and how inscrutable his ways! [34] "For who has known the mind of the Lord, or who has been his counselor?"

The Body of Christ (a Living, Organic, Growing Thing)

Ephesians 1:22-23 . . . the church, [23] which is his body, the fulness of him who fills all in all. (cf. 4:12; 5:23; Rom 7:4; 1 Cor 10:16; 12:27; Col 1:24)

Ephesians 2:19-21 So then you are no longer strangers and sojourners, but you are fellow citizens with the saints and members of the household of God, [20] built upon the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, [21] in whom the whole structure is joined together and grows into a holy temple in the Lord;

Ephesians 4:15-16 Rather, speaking the truth in love, we are to grow up in every way into him who is the head, into Christ, [16] from whom the whole body, joined and knit together by every joint with which it is supplied, when each part is working properly, makes bodily growth and upbuilds itself in love.

Colossians 2:18-19 Let no one disqualify you, insisting on self-abasement and worship of angels, taking his stand on visions, puffed up without reason by his sensuous mind, [19] and not holding fast to the Head, from whom the whole body, nourished and knit together through its joints and ligaments, grows with a growth that is from God.

Development of Catholic Doctrine: Evolution, Revolution, or an Organic Process? [book, June 2002, 198p]

The Quotable Newman: A Definitive Guide to His Central Thoughts and Ideas [book, 12 October 2012, 415p]