Albert Barnes Commentary 2 Samuel 8:6

"Then David put garrisons in Syria of Damascus; and the Syrians became servants to David, and brought tribute. And Jehovah gave victory to David whithersoever he went." — 2 Samuel 8:6 (ASV)

Garrisons - The word is used for “officers” in 1 Kings 4:5 and 1 Kings 4:19, and some believe this is its meaning here. However, it is perhaps best to understand it in the same sense as the King James Version does in 1 Samuel 10:5 and 1 Samuel 13:3.

Brought gifts - Rather, the term means “tribute,” as it also does in 2 Samuel 8:2, indicating that they became subject and tributary.