65. And I knew him not. The testification having been set forth, here is placed its corroboration or certitude, which is described in this order. First is touched upon the mode of arriving at certitude; second, the certifying sign; third, the certain testimony.
(Vers. 31.). First, therefore, is touched upon the mode of arriving at certitude, which was through the act of baptizing; therefore he says: I knew him not, that is, I was not certain concerning him; but that he might be made manifest in Israel, for this reason I came baptizing in water. He said this very thing in Mark one: "I have baptized you with water, but he shall baptize you with the Holy Spirit."
66. (Vers. 32.). And John bore witness. Here the second point is touched upon, namely the certifying sign, which indeed was the descent of the Holy Spirit; therefore he says: And John bore witness, as one who was certain, saying: Because I saw the Spirit descending as a dove from heaven; Luke 3: "The Holy Spirit descended in bodily form as a dove upon him." And remaining upon him, because he rested in him; Isaiah 11: "The Spirit of the Lord shall rest upon him." And this was the sign certifying him; therefore he says:
67. (Vers. 33.). And I knew him not before, but by this sign I knew him, because it was given to me by God; therefore he adds: But he who sent me to baptize in water, namely God; above, in the same chapter: "There was a man sent from God." He, I say, said to me: Upon whom you shall see the Spirit descending and remaining upon him, he it is who baptizes in the Holy Spirit, because baptism is given in his name alone and by his power: Acts 2: "Let each one of you be baptized in the name of Christ." The sign of this was the descent and abiding of the Holy Spirit; whence Bede: "In the Mediator alone the Spirit remained perpetually; because from that time when he began to become man, he was conceived by his ministry and operation." Therefore by this sign he was certified.
68. (Vers. 34.). And I saw etc. Here the third point is touched upon, namely the certain testimony. For the testimony is certain when a man testifies concerning what he has seen. Therefore he says: And I saw and bore witness that this is the Son of God: below, chapter 19: "And he who saw bore witness, and his testimony is true."
Questions.
69. Question I. But here it is first asked concerning the descent of the Holy Spirit.
For if the Holy Spirit is God, and God is everywhere, then he does not descend. If you say that he did not descend by essence but by effect: against: No new effect was conferred upon Christ, because he had no gift of grace then that he did not have from the conception: therefore he did not descend by effect.
Question II. Likewise I ask: why is he said to have descended in that dove rather than in another? For either he was united to that dove or not; if so, then he assumed that creature; if not, then he was equally in it as in any other: therefore he descended in any dove whatsoever.
Question III. Likewise, why did he descend in a dove rather than in some other thing?
I respond: It must be said that God is said to be in creatures in four ways: in the first way, purely by reason of being: and thus he is in all things and equally, and neither descends nor moves nor withdraws.
In the second way, by reason of signifying or showing; thus God was said to be in those creatures which signified him, as on Mount Sinai and in the cloud.
In the third way, by reason of bestowing grace: thus he is said to be in those whom he loves and who love him.
Fourth, by reason of uniting or assuming; thus in Christ.
In the first mode of existing, therefore, because it is universal and common, neither descent nor ascent corresponds to it; but in the other modes they do. Hence God is said sometimes to descend when a creature that signifies Him descends; sometimes when He confers grace; sometimes when the assumed nature descends.
Since, therefore, that dove was instituted for this purpose and specially manifested the Spirit, He is said to have descended in it, not in another, not by reason of effect or union, but of manifestation.
70. To the question: why did He manifest Himself through a dove rather than something else? The response is: on account of the properties of the dove, because the dove is a simple animal, gentle and fruitful. The Holy Spirit, however, is benign and fruitful and without guile: "For the Holy Spirit will flee from the feigned."
71. Question IV. It is also asked here concerning what he says: I did not know him. To the contrary: John bore witness concerning Christ before he baptized Him, as was set forth above; therefore either he knew Him beforehand, or he bore witness concerning what he did not know.
The response according to Chrysostom is that he knew Him in general: for he well knew that Christ had come, and that he himself was His precursor; but nevertheless he did not recognize Him personally and individually, because he had been in the desert from infancy and had not seen Him.
But this response cannot stand, because John recognized the Lord in the womb of his mother; how did he not recognize Him when he had already grown so much?
Likewise, in Matthew chapter three it is said: "I ought to be baptized by you."
The response is that he knew that He was the Christ, but he did not know that He had reserved to Himself the power of baptizing.
But then it is objected: either concerning the power of baptizing exteriorly, or concerning the power of baptizing interiorly; in either way it is false, because he ought to have known both.
I respond: It must be said that if one speaks of Christ with respect to His substance, that he did not know Him is to be understood as: supply: so certainly as he knew Him after the sign. If with respect to the power of baptizing, it is to be understood that the power of baptizing is fivefold, namely of authority, cooperation, invocation, excellence, and ministry.
The first He gave to no one, nor could He give it; the last He gave; the three intermediate ones He did not give; but the power of excellence and of invocation He could have given, but He was unwilling, lest the unity of the Church be broken. Concerning the power of cooperation, the Master of the Sentences says that he was in doubt, but nevertheless it is commonly held that He could not give it; and concerning that he did not doubt, but concerning the third and fourth he could have doubted.