not be sent visibly.

Reply Obj. 2: The Father is manifested by the voice, only as
producing the voice or speaking by it. And since it is proper to the
Father to produce the Word--that is, to utter or to speak--therefore
was it most becoming that the Father should be manifested by a voice,
because the voice designates the word. Wherefore the very voice to
which the Father gave utterance bore witness to the Sonship of the
Word. And just as the form of the dove, in which the Holy Ghost was
made manifest, is not the Nature of the Holy Ghost, nor is the form
of man in which the Son Himself was manifested, the very Nature of
the Son of God, so neither does the voice belong to the Nature of the
Word or of the Father who spoke. Hence (John 5:37) our Lord says:
"Neither have you heard His," i.e. the Father's, "voice at any time,
nor seen His shape." By which words, as Chrysostom says (Hom. xl in
Joan.), "He gradually leads them to the knowledge of the
philosophical truth, and shows them that God has neither voice nor
shape, but is above all such forms and utterances." And just as the
whole Trinity made both the dove and the human nature assumed by
Christ, so also they formed the voice: yet the Father alone as
speaking is manifested by the voice, just as the Son alone assumed
human nature, and the Holy Ghost alone is manifested in the dove, as
Augustine [*Fulgentius, De Fide ad Petrum] makes evident.

Reply Obj. 3: It was becoming that Christ's Godhead should not be
proclaimed to all in His nativity, but rather that It should be
hidden while He was subject to the defects of infancy. But when He
attained to the perfect age, when the time came for Him to teach, to
work miracles, and to draw men to Himself then did it behoove His
Godhead to be attested from on high by the Father's testimony, so
that His teaching might become the more credible. Hence He says (John
5:37): "The Father Himself who sent Me, hath given testimony of Me."
And specially at the time of baptism, by which men are born again
into adopted sons of God; since God's sons by adoption are made to be
like unto His natural Son, according to Rom. 8:29: "Whom He foreknew,
He also predestinated to be made conformable to the image of His
Son." Hence Hilary says (Super Matth. ii) that when Jesus was
baptized, the Holy Ghost descended on Him, and the Father's voice was
heard saying: "'This is My beloved Son,' that we might know, from
what was accomplished in Christ, that a