'It is I' in the Bible

Then Absalom commanded his young men, saying, "Mark when Amnon's heart is merry with wine; and when I bid you smite Amnon, then kill him. Fear not, for it is I that bid you. Be bold therefore and play the lusty bloods."

Then spake David unto the LORD when he saw the Angel that smote the people, and said, "Lo, it is I that have sinned, and I that have done wickedly. But these sheep what have they done? Let I pray thee thine hand be on me and on my father's house."