Albert Barnes Commentary 2 Samuel 8:13

"And David gat him a name when he returned from smiting the Syrians in the Valley of Salt, even eighteen thousand men." — 2 Samuel 8:13 (ASV)

The Syrians - Read "the Edomites," as in the marginal references (compare the title of Psalm 60) and as the context of 2 Samuel 8:14 requires. For a further account of this war of extermination with Edom, see 1 Kings 11:15–16. The war with Edom was of some duration, not without serious reverses and dangers to the Israelites (see the note on 2 Samuel 8:2). The different accounts probably relate to different parts of the campaign.