As far as Hamath, David also defeated King Hadadezer of Zobah, who had marched out to establish his dominion along the Euphrates River.
After this, it is said (Ch1 18:1), David did those great exploits. After the sweet communion he had had with God by the word and prayer, as mentioned in the foregoing chapter, he went on his work with extraordinary vigour and courage, conquering and to conquer. Thus Jacob, after his vision, lifted up his feet, Gen 29:1.
Commenting on 1 Chronicles 18:1-8
DAVID SMITES HADADEZER AND THE SYRIANS. (Ch1 18:3-17) Hadarezer--or, "Hadadezer" (Sa2 8:3), which was probably the original form of the name, was derived from Hadad, a Syrian deity. It seems to have become the official and hereditary title of the rulers of that kingdom.
1Ch 18:1-17 The events recorded in these three chapters are all narrated in the second book of Samuel also, and in the same order. First, there are grouped together in our 18th chapter, and in 2 Sam 8, in such a manner as to afford a general view of the whole, all the wars which David carried on victoriously against all his enemies round about...
Commenting on 1 Chronicles 18:1-17