'Testify' in the Bible

This man came as a witness, to testify about the Light, so that all might believe [in Christ, the Light] through him.

“If I alone testify about Myself, My testimony is not valid.

You search and keep on searching and examining the Scriptures because you think that in them you have eternal life; and yet it is those [very Scriptures] that testify about Me;

Jesus replied, “Even if I do testify on My own behalf, My testimony is valid, because I know where I came from and where I am going; but you do not know where I come from or where I am going.

“But when the Helper (Comforter, Advocate, Intercessor—Counselor, Strengthener, Standby) comes, whom I will send to you from the Father, that is the Spirit of Truth who comes from the Father, He will testify and bear witness about Me.

But you will testify also and be My witnesses, because you have been with Me from the beginning.