Clement of Alexandria, Miscellanies 10

It is entirely reasonable that the divinely inspired apostle declares the mystery was made known to him by revelation, just as he wrote briefly, so that when you read it you may grasp his insight into the mystery of Christ (Ephesians 3:3-4). That mystery was not disclosed to the sons of men in earlier generations, but it has now been revealed to his holy apostles and prophets (Ephesians 3:5). There is indeed a perfection of knowledge, and concerning it he writes to the Colossians: "We have not ceased praying for you and asking that you may be filled with the knowledge of his will in all wisdom and spiritual understanding, so that you may walk worthily of the Lord, fully pleasing to him, bearing fruit in every good work and growing in the knowledge of God, being strengthened with all power according to the might of his glory" (Colossians 1:9-10). Again, in line with the stewardship of God entrusted to me for your sake, he says he became a minister to fulfill the word of God — the mystery hidden from the ages and from generations, but now made manifest to his saints, to whom God chose to make known the riches of the glory of this mystery among the nations (Colossians 1:25-27).

Thus other mysteries that were concealed until the apostles and then handed down by them as received from the Lord — hidden in the Old Covenant — have now been revealed to the saints; but the riches of the glory of the mystery among the nations is something different: it is the faith and hope that rest on Christ, whom he elsewhere calls the foundation (1 Corinthians 3:11). Once more, as if eager to display this knowledge, he writes: "We admonish everyone with all wisdom, that we may present everyone mature in Christ" (Colossians 1:28). He does not mean every person without distinction, for then no one would be an unbeliever; nor does he mean that every believer is already mature in Christ. Rather, by "every person" he means, so to speak, the whole person — purified in body and soul. Since not everyone possesses this knowledge, he adds explicitly that they are "knit together in love, and to all the riches of the full assurance of understanding, to the knowledge of the mystery of God, namely Christ, in whom are hidden all the treasures of wisdom and knowledge" (Colossians 2:2-3).

"Continue steadfastly in prayer, being watchful in it with thanksgiving" (Colossians 4:2); and thanksgiving is offered not only for the soul and spiritual blessings, but also for the body and the goods of the body. He makes it even clearer that not everyone possesses this knowledge when he adds: "At the same time, pray also for us, that God may open to us a door for the word, to declare the mystery of Christ, on account of which I am in prison — that I may make it clear, as I ought to speak" (Colossians 4:3-4). For there were certain things handed down without writing. At once, to the Hebrews he says: since they ought to be teachers by reason of time, they have become, as it were, aged in the Old Covenant; yet you have need again for someone to teach you the elementary principles of the oracles of God, and you have become those who need milk and not solid food (Hebrews 5:12).