281 Now it happened in those days that the Philistines gathered their armies together for war, to fight with Israel. And Achish said to David, "You assuredly know that you will go out with me to battle, you and your men." 2 And David said to Achish, "Surely you know what your servant can do." And Achish said to David, "Therefore I will make you one of my chief guardians forever."
3 Now Samuel had died, and all Israel had lamented for him and buried him in Ramah, in his own city. And Saul had put the mediums and the spiritists out of the land. 4 Then the Philistines gathered together, and came and encamped at Shunem. So Saul gathered all Israel together, and they encamped at Gilboa.
Matthew Henry's Commentary on 1 Samuel 28:1-4
Commentary on 1 Samuel 28:1-6
(Read 1 Samuel 28:1-6)
David could not refuse Achish without danger. If he promised assistance, and then stood neuter, or went over to the Israelites, he would behave with ingratitude and treachery. If he fought against Israel, he would sin greatly. It seemed impossible that he should get out of this difficulty with a clear conscience; but his evasive answer, intended to gain time, was not consistent with the character of an Israelite indeed. Troubles are terrors to the children of disobedience. In his distress, Saul inquired of the Lord. He did not seek in faith, but with a double, unstable mind. Saul had put the law in force against those that had familiar spirits, Exodus 22:18. Many seem zealous against, sin, when they are any way hurt by it, who have no concern for the glory of God, nor any dislike of sin as sin. Many seem enemies to sin in others, while they indulge it in themselves. Saul will drive the devil out of his kingdom, yet harbours him in his heart by envy and malice. How foolish to consult those whom, according to God's law, he had endeavoured to root out!