1 Samuel 27:8

Pillaged Gessuri, &c. These probably were enemies of the people of God; and some, if not all of them, were of the number of those whom God had ordered to be destroyed; which justifies David's proceedings in their regard. Though it is to be observed here, that we are not under an obligation of justifying every thing that he did: for the Scripture, in relating what was done, doth not say that it was well done. And even such as are true servants of God, are not to be imitated in all they do. (Challoner) --- The nations of Chanaan, who inhabited as far as Egypt, and the Amalecites, who had escaped the arms of Saul, were devoted to destruction, Exodus xvii., &c. In such cases, any man might fall upon them, without any other formal declaration of war. (Calmet) --- There was another Gessuri of Syria, in the tribe of Manasses, across the Jordan. (Menochius) --- The country which these people inhabited, to the south of Palestine, was afterwards depopulated by the kings of Egypt and of Syria, in their continual wars, so that many of the cities which are mentioned in Scripture, were never known to profane geographers. (Calmet) --- St. Jerome, (Trad.) Sa, and others, think that David attacked some of the Philistines. But it is as probable at least that he would abstain from molesting them, whom had so generously afforded him an asylum. Salien concludes, that he did not attack the other nations, (except the Amalecites, who were sufficiently marked out for destruction, Deuteronomy xxv. 19,) without consulting the Lord, by the high priest, as he was accustomed to do in every difficulty. (Salien, the year of the world 2979) (Menochius) --- They all dwelt in part of the land of Chanaan, (Worthington) which was sufficient. (Haydock)