8 Now David and his men went up, and made raids upon the Gesh'urites, the Gir'zites, and the Amal'ekites; for these were the inhabitants of the land from of old, as far as Shur, to the land of Egypt. 9 And David smote the land, and left neither man nor woman alive, but took away the sheep, the oxen, the asses, the camels, and the garments, and came back to A'chish. 10 When A'chish asked, "Against whom have you made a raid today?" David would say, "Against the Negeb of Judah," or "Against the Negeb of the Jerah'meelites," or, "Against the Negeb of the Ken'ites." 11 And David saved neither man nor woman alive, to bring tidings to Gath, thinking, "Lest they should tell about us, and say, 'So David has done.'" Such was his custom all the while he dwelt in the country of the Philistines. 12 And A'chish trusted David, thinking, "He has made himself utterly abhorred by his people Israel; therefore he shall be my servant always."
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.