After the above statements, he continues: “If he wished to remain hid, why was there heard a voice from heaven proclaiming him to be the Son of God? And if he did not seek to remain concealed, why was he punished? Or why did he die?” Now, by such questions he thinks to convict the histories of discrepancy, not observing that Jesus neither desired all things regarding Himself to be known to all whom He happened to meet, nor yet all things to be unknown. Accordingly, the voice from heaven which proclaimed Him to be the Son of God, in the words, “This is my beloved Son, in whom I am well pleased,” is not stated to have been audible to the multitudes, as this Jew of Celsus supposed.
The voice from the cloud on the high mountain, moreover, was heard only by those who had gone up with Him. For the divine voice is of such a nature, as to be heard only by those whom the speaker wishes to hear it. And I maintain, that the voice of God which is referred to, is neither air which has been struck, nor any concussion of the air, nor anything else which is mentioned in treatises on the voice; and therefore it is heard by a better and more divine organ of hearing than that of sense.
And when the speaker will not have his voice to be heard by all, he that has the finer ear hears the voice of God, while he who has the ears of his soul deadened does not perceive that it is God who speaks. These things I have mentioned because of his asking, “Why was there heard a voice from heaven proclaiming him to be the Son of God?” while with respect to the query, “Why was he punished, if he wished to remain hid?” what has been stated at greater length in the preceding pages on the subject of His suffering may suffice.
Source: Against Celsus (New Advent)