8 From time to time David and his men raided the Geshurites, the Girzites, and the Amalekites - these people were longtime inhabitants of the land stretching toward Shur and on to Egypt. 9 When David raided an area he left no one alive, neither man nor woman, but took everything else: sheep, cattle, donkeys, camels, clothing - the works. Then he'd return to Achish. 10 Achish would ask, "And whom did you raid today?" 11 He never left a single person alive lest one show up in Gath and report what David had really been doing. This is the way David operated all the time he lived in Philistine country. 12 Achish came to trust David completely. He thought, "He's made himself so repugnant to his people that he'll be in my camp forever."
Matthew Henry's Commentary on 1 Samuel 27:8-12
Commentary on 1 Samuel 27:8-12
(Read 1 Samuel 27:8-12)
While David was in the land of the Philistines, he attacked some remains of the devoted nations. The people whom he cut off were long before doomed to destruction. It is often wisdom to shun public notice, but we must in no situation be idle. We must always try to do somewhat in the cause of God. This expedition David hid from Achish. But an equivocation which serves the purpose of a lie, is as like to it as a hypocrite is to a profane person, it is only better in appearance, therefore more dangerous. Yet, though believers often manifest imperfections, they can never be prevailed upon to renounce the service of God, and to unite interests with his enemies, or finally to become the servants of sin and Satan. But what a train of evils follow from unbelief! When we forget the Lord's past mercies, and his gracious assurances, we shall be overwhelmed with desponding fears, and probably be led to adopt some dishonourable method to get rid of our troubles. Nothing can so effectually establish us in holy tempers and practices, and preserve us from perplexities, as firm, unshaken dependence upon the promises of God in Christ Jesus.