1 Samuel 24:3, 8

On the way he came to the sheepfolds where there was a cave; and Saul went in to relieve himself. Now David and his men were sitting in the cave’s innermost recesses.

Then David also got up afterward and went out of the cave and called after Saul, saying, “My lord the king!” And when Saul looked behind him, David bowed with his face to the ground and lay himself face down.