Mark 1:11

And there came a voice from heaven
What the Jews call "Bath Kol", saying,

thou art my beloved Son, in whom I am well pleased:
it is in Matthew, "this is my beloved Son", ( Matthew 3:17 ) ; as if the words were spoken to others, to John, the administrator of baptism to him, and to those that were spectators; directing them to Christ, on whom the Spirit now descended, and testifying to them how great a person he was, how nearly related to God; how much he was the object of his love, and what a pleasure and delight he took in him; but here they are delivered as an immediate address to Christ himself, "thou art my beloved Son". Christ, as he was the only begotten Son of God from eternity, so his filiation was owned and declared to him as early, ( Psalms 2:7 ) . This therefore was not the first time, nor was it only for his sake that this was said unto him, but also for the sake of those that stood by: but it may be observed, that he is not only called his Son, but his "beloved Son"; which might be necessary to be said to him in his state of humiliation, whilst he was yielding obedience to the will of God, and fulfilling all righteousness; and when he was about to be, as he quickly after this was, tempted by Satan in the wilderness, by whom his sonship was called in question. Now these words being directed to Christ, show that the former are spoken of him, and are applicable to him, as well as to John; (See Gill on Matthew 3:17).