Juan 8:14

Jesus corrected His critics’ false conclusion. Even if Jesus was the only witness to His own identity, His witness would still be true. Frequently only one person knows the facts. Jesus’ witness was not false because it stood alone even though it was insufficient under Mosaic Law. The Pharisees had misunderstood Him. Consequently He proceeded to review His former teaching in somewhat different terms (cf. John 5:19-30; John 5:36-37).

Jesus claimed to offer true (Gr. alethes, cf. John 5:31) testimony because He knew His own origin and destiny (cf. John 7:29; John 7:33-34). His critics knew neither of these things.