Matthew Poole and continuators on 1 Samuel 21:10

10 ¶ And David arose, and fled that day for fear of Saul, and went to Achish the king of Gath :

A strange Action: but it must be considered, 1. That Saul's Rage was so great and implacable: his Power also, and diligence in hunting after him so great, that he despaired of escaping him other way: and it is not strange if a desperate Disease, produceth a desperate Remedy. 2. David might reasonably think, that being Persecuted, and Banished by Saul, and the Israelites under his Command, he should be welcome to the Philistines; who would be glad, not onely to be freed from all those Evils which he had from time to time done, and was likely further to do to them, but also to make him their Friend, and oblige him by their kindness; and to make him the more odious and irreconcilable to Saul and the Israelites. Qu. But why did he go to these, and not rather to some other neighbour Nation? Ans. Because they were all at Peace with Saul; and therefore would certainly have delivered him up, upon Saul's Demands.

Marginal references: Abimelech. Psal. 34. title.