1 Samuel 24:3-7

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. And afterward David’s heart struck him, because he had cut off a corner of Saul’s robe. He said to his men, “The LORD forbid that I should do this thing to my lord, the LORD’s anointed, to put out my hand against him, seeing he is the LORD’s anointed.” So David persuaded his men with these words and did not permit them to attack Saul. And Saul rose up and left the cave and went on his way.