John 8:14

Though I bear record Better, even if I bear witness. God can testify respecting Himself, and there are truths to which He alone can testify. Yet He condescends to conform to the standard of human testimony, and adds to His witness the words and works of His incarnate Son; who in like manner can bear witness of Himself, being supported by the witness of the Father (John 8:16).

and whither I go i.e. by Death and Ascension.

but ye cannot tell Better, But ye know not. They knew neither of these points respecting themselves; how should they know it respecting Him? Man knows not either the origin or the issue of his life. -Ye" is emphatic.

whence I came, and whither I go For -and" read or with the best MSS. Note the change from -came," which refers to the Incarnation, His having once come from the Father, to -come," which refers to His perpetual presence with mankind. Note also the balanced parallelism of the verse and comp. John 8:35; John 8:38, John 7:6.