Garrisons were groups of soldiers placed in a territory to keep control and prevent rebellion. David placed army garrisons in Aram, but not in Moab (2 Samuel 8:2). This difference suggests that Aram was a stronger and more dangerous enemy. David needed a military presence there in order to keep control.
the LORD made David victorious: See 2 Samuel 8:14. God was the true source of David’s success and growing power.