5 Afterward David was stricken to the heart because he had cut off a corner of Saul's cloak. 6 He said to his men, "The Lord forbid that I should do this thing to my lord, the Lord's anointed, to raise my hand against him; for he is the Lord's anointed." 7 So David scolded his men severely and did not permit them to attack Saul. Then Saul got up and left the cave, and went on his way.
Matthew Henry's Commentary on 1 Samuel 24:5-7
Commentary on 1 Samuel 24:1-7
(Read 1 Samuel 24:1-7)
God delivered Saul into David's hand. It was an opportunity given to David to exercise faith and patience. He had a promise of the kingdom, but no command to slay the king. He reasons strongly, both with himself and with his men, against doing Saul any hurt. Sin is a thing which it becomes us to startle at, and to resist temptations thereto. He not only would not do this bad thing himself, but he would not suffer those about him to do it. Thus he rendered good for evil, to him from whom he received evil for good; and was herein an example to all who are called Christians, not to be overcome of evil, but to overcome evil with good.