Verses with the word testifying in the New Testament (3 verses):

Acts 20:21
Testifying both to the Jews, and also to the Greeks, repentance toward God, and faith toward our Lord Jesus Christ.

Hebrews 11:4
By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained witness that he was righteous, God testifying of his gifts: and by it he being dead yet speaketh.

1 Peter 5:12
By Silvanus, a faithful brother unto you, as I suppose, I have written briefly, exhorting, and testifying that this is the true grace of God wherein ye stand.