v1-2: The skirmish against the Philistines was a diversion from Saul's main task of pursuing David. How sad that he should be so committed to such a task. Again, David was betrayed, this time by the people of En-Gedi.
v3-4: There was, for the first time, an opportunity for David to kill Saul. This incident demonstrates the character of David, his sensitive conscience, his humility, his respect for God's anointed.
David's men spoke of God speaking about delivering David's enemy into his hands. The NIV marginal reading seems more helpful; "Today the Lord is saying, 'I will give your enemy...'" David tested this statement against the principles of God's word.
v5-7: David was conscience stricken even by cutting off the corner of Saul's robe. This would indicate to Saul that David could have killed him.
David acknowledged Saul's anointing, for God had called him to be king, even though he had departed from the Lord. This principle guided David. Where opportunities and circumstances indicate one course of action, we are still obliged to follow the principles of God's word.
David also had to deal with his men, who were keen to have Saul killed. His words were clear, and he rebuked his men, and expected them to live by the same principles.
v8-10: "My lord the king!" David showed respect for Saul; such was his graciousness toward the man who was trying to kill him. David was content to wait for God's time, for God had promised the throne, and His word would be fulfilled. He would not manipulate the circumstances by killing Saul, even though he would have become king as a result.
v11-13: The corner of Saul's robe was evidence of David's innocence, and Saul and his men knew it. David stated his promise, "my hand will not touch you". Unlike Saul, David was a man of his word.
v14-15: 'Don't waste your time' said David, "Whom are you pursuing? A dead dog? A flea?" He insists that he is not worth pursuing, see also 18.23. In a world that pursues reputation, David wanted none. All he wanted was the Lord's blessing and vindication.
v16-21: Saul's words show some regret and sorrow. He acknowledged that David had not retaliated, and had not killed Saul when he had opportunity. He also asked David to care for his family after his death, in a request echoing that of Jonathan (20.15)..
v22: David, still full of grace, gave his promise to Saul, and returned to the strongholds of Judah.