Adam Clarke on 1 Samuel 22:2

And every one that was in distress - debt - discontented - It is very possible that these several disaffected and exceptionable characters might at first have supposed that David, unjustly persecuted, would be glad to avail himself of their assistance that he might revenge himself upon Saul, and so they in the mean time might profit by plunder, etc. But if this were their design they were greatly disappointed, for David never made any improper use of them. They are never found plundering or murdering; on the contrary, they always appear under good discipline, and are only employed in services of a beneficent nature, and in defense of their country. Whatever they were before they came to David, we find that he succeeded in civilizing them, and making profitable to the state those who were before unprofitable. It is not necessary to strain the words of the original in order to prove that these were oppressed people, and not exceptionable characters, as some have done.