'Bears Witness' in the Bible

There is another who bears witness of Me, and I know that the witness which He witnesses of Me is true.

I am one who bears witness of Myself, and the Father who sent Me bears witness concerning Me.

as also the high priest bears witness to me, and all the elderhood. And receiving letters from them to the brothers, I traveled into Damascus indeed to lead those being bound to Jerusalem, in order that they might be punished.

The Spirit Himself bears witness with our spirit that we are the children of God.

This is He who came through water and blood, Jesus Christ, not by water only, but by the water and blood. And the Spirit is He who bears witness, because the Spirit is the truth.