1 Samuel 24:3, 8

And he came to the sheepfolds by the way, where there was a cave, and Saul went in to relieve himself. Now David and his men were sitting in the innermost parts of the cave.

Afterward David also arose and went out of the cave, and called after Saul, “My lord the king!” And when Saul looked behind him, David bowed with his face to the earth and paid homage.