John Wesley on 1 Samuel 22:2

Debt - Probably poor debtors, whom the creditors were obliged to spare, Exod 22:25. And though their persons were with David, yet their lands and goods were liable to their creditors. Captain over them - He did not maintain any injustice or wickedness, which some of them possibly might be guilty of; but on the contrary, he instructed and obliged them to the practice of all justice and honesty.