'It is I' in the Bible

As they grappled with one another, each one stabbed his opponent with his sword and they fell dead together. So that place is called the Field of Flints; it is in Gibeon.

When he saw the angel who was destroying the people, David said to the Lord, "Look, it is I who have sinned and done this evil thing! As for these sheep -- what have they done? Attack me and my family."