John 10:41
10:41 Many came to him and began to say, “John performed no miraculous sign, but everything John said about this man was true!”
John 19:35
19:35 And the person who saw it has testified (and his testimony is true, and he knows that he is telling the truth), so that you also may believe.
John 21:24
A Final Note
21:24 This is the disciple who testifies about these things and has written these things, and we know that his testimony is true.