John 21:24
This is the disciple who is bearing witness about these things, and who has written these things, and we know that his testimony is true.
John 19:35
He who saw it has borne witness--his testimony is true, and he knows that he is telling the truth--that you also may believe.
3 John 1:12
Demetrius has received a good testimony from everyone, and from the truth itself. We also add our testimony, and you know that our testimony is true.
John 15:27
And you also will bear witness, because you have been with me from the beginning.
1 John 1:1-2
That which was from the beginning, which we have heard, which we have seen with our eyes, which we looked upon and have touched with our hands, concerning the word of life--
1 John 5:6
This is he who came by water and blood--Jesus Christ; not by the water only but by the water and the blood. And the Spirit is the one who testifies, because the Spirit is the truth.