I am one that bear witness of myself,.... As he does of his sonship, in 1 John 5:7.
And the Father that sent me, beareth witness of me; as he did, by the descent of the Spirit upon him at his baptism, and by a voice from heaven, both at that time, and at his transfiguration, and by the miracles which he wrought; and particularly he bore testimony of him, long before, in prophecy, that he was the light of the world he now said he was, Isaiah 42:6; so that here were two testifiers, his Father and himself; which show them to be two distinct divine persons, and equal to each other: and now if the testimony of two men is true, firm, and authentic, and to be depended upon and received, then much more the testimony of two divine persons; see 1 John 5:9.