John 21:24

This, is the disciple who beareth witness concerning these things, and who hath written these things; and we know that, true, is, his witness.

John 19:35

And, he that hath seen, hath borne witness; and, genuine, is his testimony, and, he, knoweth that he saith, what is true, that, ye also, may believe.

John 15:27

And do, ye also, bear witness, because, from the beginning, ye are, with me,

1 John 1:1-2

That which was from the beginning, which we have heard, which we have seen with our eyes, which we for ourselves gazed upon, and our hands did handle, concerning the Word of Life, -

1 John 5:6

This, is he that came through means of water and blood, Jesus Christ: not, by the water, only, but, by the water and by the blood, - and, the Spirit, it is, that is bearing witness, because, the Spirit, is the truth.

Treasury of Scripture Knowledge

Summary

This is the disciple which testifieth of these things, and wrote these things: and we know that his testimony is true.

Bible References

We know

John 19:35
And, he that hath seen, hath borne witness; and, genuine, is his testimony, and, he, knoweth that he saith, what is true, that, ye also, may believe.
1 John 1:1
That which was from the beginning, which we have heard, which we have seen with our eyes, which we for ourselves gazed upon, and our hands did handle, concerning the Word of Life, -
1 John 5:6
This, is he that came through means of water and blood, Jesus Christ: not, by the water, only, but, by the water and by the blood, - and, the Spirit, it is, that is bearing witness, because, the Spirit, is the truth.