1 Samuel 24:3-4

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. And the men of David said to him, “Here is the day of which the LORD said to you, ‘Behold, I will give your enemy into your hand, and you shall do to him as it shall seem good to you.’” Then David arose and stealthily cut off a corner of Saul’s robe.