MenofBelial - This is a common expression to denote the sour, the rugged, the severe, the idle, and the profane.
Matthew Henry
Concise Bible Commentary
What God gives us, he designs we should do good with. In distributing the spoil, David was just and kind. Those are men of Belial indeed, who delight in putting hardships upon their brethren, and care not who is starved, so that they may be fed to the full. David was generous and kind to all his friends. Those who consider the Lord as the Giver of their abundance, will dispose of it with fairness and liberality.