John 8:14

Though I bear record of myself-my record is true; he had before said, "If I bear witness of myself, my witness is not true," chap John 5:31; but there he was speaking of the validity of testimony according to the human rule of trying it. Here, on the contrary, he speaks of the quality of his own testimony from the high consciousness of his divine nature and mission.

I know whence I came-whither I go; I know that I come from the Father and return again to him; therefore I know that my testimony of him is true.

Ye cannot tell; more literally, Ye know not, as in the first part of the verse. As the Jews did not understand his divine nature and mission, they were not qualified to judge of his testimony.