24 This is the disciple who is testifying about these things, and who has written down these things. And we know that his testimony is true.
John 21:24 Cross References - LEB
John 15:27
27 And you also will testify, because you have been with me from the beginning.
John 19:35
35 And the one who has seen it* has testified, and his testimony is true, and that person knows that he is telling the truth, so that you also may believe.
1 John 1:1-2
1 What was from the beginning, what we have heard, what we have seen with our eyes, what we have looked at and our hands have touched, concerning the word of life—
2 and the life was revealed, and we have seen and testify and announce to you the eternal life which was with the Father and was revealed to us—
1 John 5:6
6 This is the one who came by water and blood—Jesus Christ, not with the water only, but with the water and with the blood. And the Spirit is the one who testifies, because the Spirit is the truth.
3 John 1:12
12 Demetrius has been testified to by all, even by the truth itself. And we also testify to him, and you know that our testimony is true.