Charles Ellicott Commentary 1 Chronicles 18:1-3

"And after this it came to pass, that David smote the Philistines, and subdued them, and took Gath and its towns out of the hand of the Philistines. And he smote Moab; and the Moabites became servants to David, and brought tribute. And David smote Hadarezer king of Zobah unto Hamath, as he went to establish his dominion by the river Euphrates." — 1 Chronicles 18:1-3 (ASV)

Subjugation of the Philistines, Moabites, and Arameans of Zobah.