1 Samuel 24:3, 8

And he came to the sheepcotes by the way, where was a cave; and Saul went in to cover his feet: and David and his men remained in the sides of the cave.

David also arose afterward, and went out of the cave, and cried after Saul, saying, My lord the king. And when Saul looked behind him, David stooped with his face to the earth, and bowed himself.