Note 1 at Jn. 8:14: The scripture does say in Proverbs 27:2, "Let another man praise thee, and not thine own mouth; a stranger, and not thine own lips." The scripture also states that it takes the testimony of at least two or preferably three people to establish any truth (see parallel scriptures for v. 17). Jesus needed more than the witness of Himself, and He had it through the witness of the Father (v. 18), the witness of His works (Jn. 5:36), and the witness of John the Baptist (Jn. 5:32-33).

However, Jesus was in a unique situation. As stated in this verse, Jesus was the only one who knew His true origin and destination. He had to testify about Himself and then let His works and His Father (through the witness of the Holy Spirit--Jn. 5:37) confirm His words.