Rightly, then, the apostle says that it was by revelation that he knew the mystery: "As I wrote afore in few words, according as ye are able to understand my knowledge in the mystery of Christ.".
Rightly, therefore, the divine apostle says, "By revelation the mystery was made known to me (as I wrote before in brief, in accordance with which, when ye read, ye may understand my knowledge in the mystery of Christ), which in other ages was not made known to the sons of men, as it is now revealed to His holy apostles and prophets."
Paul indicates that this mystery was made known to him through revelation. From this passage it is evident that a Christian, and a very excellent Christian at that, can be brought into being solely by grace.… Nevertheless, the power of God dispenses grace in many ways. Others come to faith by teaching, wherein by a legitimate training process and through the commandments of the Savior a person is reborn through the Spirit and water, so as to receive the spirit of Christ, in a teaching process that is mediated from human beings and through human beings. But what happened to Paul came to him by the grace of God through revelation. Although he, in my judgment, was the only one who received this particular revelation, God is able to reveal himself in this form or in other ways to others.
He indicates that he has been shown the revelation of the mystery of God, about which he says that he has written briefly, that is, precisely, according to their capacity to comprehend the wisdom of the apostle in the mystery of Christ.
Perhaps he had informed them of it by some persons, or had not long before been writing to them. Here he is pointing out that the whole is of God, that we have contributed nothing. For what? I ask, was not Paul himself, the wonderful, he that was so versed in the law, he that was brought up at the feet of Gamaliel according to the most perfect manner, was not he saved by grace? With good reason too does he call this a mystery, for a mystery it is, to raise the Gentiles in a moment to a higher rank than the Jews. "As I wrote afore," says he, "in few words," i.e., briefly,
The words I wrote a little before do not mean, as some think, that he has written another letter. For it is not with respect to himself that he says “I have written” but with respect to the mystery. For he is referring to “the mystery made known to me by revelation, as I wrote to you a little while ago,” yet it is this “about which I have just now written.” For this has been his subject from the outset right up to this passage.
[AD 215] Clement of Alexandria on Ephesians 3:3
Rightly, therefore, the divine apostle says, "By revelation the mystery was made known to me (as I wrote before in brief, in accordance with which, when ye read, ye may understand my knowledge in the mystery of Christ), which in other ages was not made known to the sons of men, as it is now revealed to His holy apostles and prophets."