2 Corinthians 13:1-3 NKJV

1 This will be the third time I am coming to you. "By the mouth of two or three witnesses every word shall be established."
2 I have told you before, and foretell as if I were present the second time, and now being absent I write to those who have sinned before, and to all the rest, that if I come again I will not spare--
3 since you seek a proof of Christ speaking in me, who is not weak toward you, but mighty in you.