'Testimony is True' in the Bible

The one who saw this has testified, and his testimony is true. He knows he is telling the truth so that you, too, may believe,

This is the disciple who is testifying to these things and has written them down. We know that his testimony is true.

Demetrius has received a good report from everyone, including the truth itself. We, too, can testify to this report, and you know that our testimony is true.