Matthew 3:17

Or, that from these things thus fulfilled upon Christ, we might learn that after the washing of water the Holy Spirit also descends on us from the heavenly gates, on us also is shed an unction of heavenly glory, and an adoption to be the sons of God, pronounced by the Father's voice. (de Trin. iii. 11.) He witnesses that He is His Son not in name merely, but in very kindred. Sons of God are we many of us; but not as He is a Son, a proper and true Son, in verity, not in estimation, by birth, not adoption.

(Ambrosiaster. Serm. x. 1.) And no wonder that the mystery of the Trinity is not wanting to the Lord's laver, when even our laver contains the sacrament of the Trinity. The Lord willed to show in His own case what He was after to ordain for men.

For since the voice that said, "This is my beloved Son," would seem to the multitude rather to belong to John, for it added not, "This that is baptized," but simply "This," and every hearer would conceive it to be said concerning the baptizer, rather than the baptized, partly on account of the Baptist's own dignity, partly for all that hath been mentioned; the Spirit came in form of a dove, drawing the voice towards Jesus, and making it evident to all, that "This" was not spoken of John that baptized, but of Jesus who was baptized. And how was it, one may say, that they did not believe, when these things came to pass? Because in the days of Moses also many wonderful works were done, albeit not such as these; and after all those, the voices, and the trumpets, and the lightnings, they both forged a calf, and "were joined unto Baal-peor." And those very persons too, who were present at the time, and saw Lazarus arise, so far from believing in Him, who had wrought these things, repeatedly attempted even to slay Him. Now if seeing before their eyes one rise from the dead, they were so wicked, why marvel at their not receiving a voice wafted from above? Since when a soul is uncandid and perverse, and possessed by the disease of envy, it yields to none of these things; even as when it is candid it receives all with faith, and hath no great need of these. Speak not therefore thus, "They believed not," but rather inquire, "Did not all things take place which ought to have made them believe?" For by the prophet also God frames this kind of defense of His own ways in general. That is, the Jews being on the point of ruin, and of being given over to extreme punishment; lest any from their wickedness should calumniate His providence, He saith, "What ought I to have done to this vineyard, that I have not done?" Just so here likewise do thou reflect; "what ought to have been done, and was not done?" And indeed whensoever arguments arise on God's Providence, do thou make use of this kind of defense, against those who from the wickedness of the many try to raise a prejudice against it. See, for instance, what astonishing things are done, preludes of those which were to come; for it is no more paradise, but Heaven that is opened.

On this very account the Jewish baptism ceases, and ours takes its beginning. And what was done with regard to the Passover, the same ensues in the baptism also. For as in that case too, He acting with a view to both, brought the one to an end, but to the other He gave a beginning: so here, having fulfilled the Jewish baptism, He at the same time opens also the doors of that of the Church; as on one table then, so in one river now, He had both sketched out the shadow, and now adds the truth. For this baptism alone hath the grace of the Spirit, but that of John was destitute of this gift. For this very cause in the case of the others that were baptized no such thing came to pass, but only in the instance of Him who was to hand on this; in order that, besides what we have said, thou mightest learn this also, that not the purity of the baptizer, but the power of the baptized, had this effect. Not until then, assuredly, were either the heavens opened, nor did the Spirit make His approach. Because henceforth He leads us away from the old to the new polity, both opening to us the gates on high, and sending down His Spirit from thence to call us to our country there; and not merely to call us, but also with the greatest mark of dignity. For He hath not made us angels and archangels, but He hath caused us to become "sons of God," and "beloved," and so He draws us on towards that portion of ours. Having then all this in thy mind, do thou show forth a life worthy of the love of Him who calls thee, and of thy citizenship in that world, and of the honor that is given thee. Crucified as thou art to the world, and having crucified it to thyself, show thyself with all strictness a citizen of the city of the heavens. And do not, because thy body is not translated unto heaven, suppose that thou hast anything to do with the earth; for thou hast thy Head abiding above. Yea with this very purpose the Lord, having first come here and having brought His angels, did then, taking thee with Him, depart thither; that even before thy going up to that place, thou mightest understand that it is possible for thee to inhabit earth as it were heaven.

It sate on the head of Jesus, that none might suppose the voice of the Father spoken to John, and not to the Lord. The mystery of the Trinity is shown in this baptism. The Lord is baptized; the Spirit descends in shape of a dove; the voice of the Father is heard giving testimony to the Son.