This is where we start to see David’s character as ‘a man after God’s own heart’.
In a surreal scene, David and his men were hiding in a cave, Saul was there too (relieving himself), and all Saul’s men would have been just outside, waiting. Rather than killing Saul, David cut a piece of his robe off, then conscience-stricken, approached Saul and shouted out:
1 Samuel 24:10-12 … For I said, ‘I will never harm the king—he is the Lord’s anointed one.’ Look, my father, at what I have in my hand. It is a piece of the hem of your robe! I cut it off, but I didn’t kill you. This proves that I am not trying to harm you and that I have not sinned against you, even though you have been hunting for me to kill me. May the Lord judge between us. Perhaps the Lord will punish you for what you are trying to do to me, but I will never harm you.
Saul appeared to respond, as he left without taking advantage of a good military opportunity. It didn’t last.