5 David slipped over to Saul's camp one night to look around. Saul and Abner son of Ner, the commander of his army, were sleeping inside a ring formed by the slumbering warriors.
6 "Who will volunteer to go in there with me?" David asked Ahimelech the Hittite and Abishai son of Zeruiah, Joab's brother. "I'll go with you," Abishai replied. 7 So David and Abishai went right into Saul's camp and found him asleep, with his spear stuck in the ground beside his head. Abner and the soldiers were lying asleep around him. 8 "God has surely handed your enemy over to you this time!" Abishai whispered to David. "Let me pin him to the ground with one thrust of the spear; I won't need to strike twice!" 9 "No!" David said. "Don't kill him. For who can remain innocent after attacking the Lord 's anointed one? 10 Surely the Lord will strike Saul down someday, or he will die of old age or in battle. 11 The Lord forbid that I should kill the one he has anointed! But take his spear and that jug of water beside his head, and then let's get out of here!" 12 So David took the spear and jug of water that were near Saul's head. Then he and Abishai got away without anyone seeing them or even waking up, because the Lord had put Saul's men into a deep sleep.
Matthew Henry's Commentary on 1 Samuel 26:5-12
Commentary on 1 Samuel 26:1-12
(Read 1 Samuel 26:1-12)
How soon do unholy hearts lose the good impressions convictions have made upon them! How helpless were Saul and all his men! All as though disarmed and chained, yet nothing is done to them; they are only asleep. How easily can God weaken the strongest, befool the wisest, and baffle the most watchful! David still resolved to wait till God thought fit to avenge him on Saul. He will by no means force his way to the promised crown by any wrong methods. The temptation was very strong; but if he yielded, he would sin against God, therefore he resisted the temptation, and trusted God with the event.