2 Now that on this account Christ came to His baptism, is from this evident. But wherefore was this baptism devised for Him? For that not of himself did the son of Zacharias proceed to this, but of God who moved him—this Luke also declares, when he says, “The word of the Lord came unto him,” that is, His commandment. And he himself too says, “He that sent me to baptize with water, the same said to me, upon whom you shall see the Spirit descending like a dove, and remaining on Him, the same is He which baptizes with the Holy Ghost.” Wherefore then was he sent to baptize? The Baptist again makes this also plain to us, saying, “I knew Him not, but that He should be made manifest to Israel, therefore am I come baptizing with water.”
And if this was the only cause, how says Luke, that “he came into the country about Jordan, preaching the baptism of repentance for the remission of sins?” And yet it had not remission, but this gift pertained unto the baptism that was given afterwards; for in this “we are buried with Him,” and our old man was then crucified with Him, and before the cross there does not appear remission anywhere; for everywhere this is imputed to His blood. And Paul too says, “But you are washed, but you are sanctified,” not by the baptism of John, but “in the name of our Lord Jesus Christ, and by the Spirit of our God.” And elsewhere too he says, “John verily preached a baptism of repentance,” (he says not “of remission,”) “that they should believe in Him that should come after him.” For when the sacrifice was not yet offered, neither had the spirit yet come down, nor sin was put away, nor the enmity removed, nor the curse destroyed; how was remission to take place?
What means then, “for the remission of sins?”
The Jews were senseless, and had never any feeling of their own sins, but while they were justly accountable for the worst evils, they were justifying themselves in every respect; and this more than anything caused their destruction, and led them away from the faith. This, for example, Paul himself was laying to their charge, when he said, that “they being ignorant of God's righteousness, and going about to establish their own, had not submitted themselves unto the righteousness of God.” And again: “What shall we say then? That the Gentiles, which followed not after righteousness, have attained to righteousness; but Israel, which followed after the law of righteousness, has not attained unto the law of righteousness. Wherefore? Because they sought it not by faith, but as it were by works.”
Since therefore this was the cause of their evils, John comes, doing nothing else but bringing them to a sense of their own sins. This, among other things, his very garb declared, being that of repentance and confession. This was indicated also by what he preached, for nothing else did he say, but “bring forth fruits meet for repentance.” Forasmuch then as their not condemning their own sins, as Paul also has explained, made them start off from Christ, while their coming to a sense thereof would set them upon longing to seek after their Redeemer, and to desire remission; this John came to bring about, and to persuade them to repent, not in order that they might be punished, but that having become by repentance more humble, and condemning themselves, they might hasten to receive remission.
But let us see how exactly he has expressed it; how, having said, that he “came preaching the baptism of repentance in the wilderness of Judæa,” he adds, “for remission,” as though he said, For this end he exhorted them to confess and repent of their sins; not that they should be punished, but that they might more easily receive the subsequent remission. For had they not condemned themselves, they could not have sought after His grace; and not seeking, they could not have obtained remission.
Thus that baptism led the way for this; wherefore also he said, that “they should believe in Him which should come after him;” together with that which has been mentioned setting forth this other cause of His baptism. For neither would it have been as much for him to have gone about to their houses, and to have led Christ around, taking Him by the hand, and to have said, “Believe in This Man;” as for that blessed voice to be uttered, and all those other things performed in the presence and sight of all.
On account of this He comes to the baptism. Since in fact both the credit of him that was baptizing, and the purport of the thing itself, was attracting the whole city, and calling it unto Jordan; and it became a great spectacle.
Therefore he humbles them also when they have come, and persuades them to have no high fancies about themselves; showing them liable to the utmost evils, unless they would repent, and leaving their forefathers, and all vaunting in them, would receive Him that was coming.
Because in fact the things concerning Christ had been up to that time veiled, and many thought He was dead, owing to the massacre which took place at Bethlehem. For though at twelve years old He discovered Himself, yet did He also quickly veil Himself again. And for this cause there was need of that splendid exordium and of a loftier beginning. Wherefore also then for the first time he with clear voice proclaims things which the Jews had never heard, neither from prophets, nor from any besides; making mention of Heaven, and of the kingdom there, and no longer saying anything touching the earth.
But by the kingdom in this place he means His former and His last advent.
Source: Homilies on the Gospel of St. Matthew (New Advent)