Joshua 5:14-15

14He said, “No; rather I have come now as captain of the army of the Lord.” Then Joshua fell with his face toward the earth and bowed down, and said to him, “What does my lord have to say to his servant?”

15The captain of the Lord’s army said to Joshua, “Remove your sandals from your feet, because the place where you are standing is holy (set apart to the Lord).” And Joshua did so.