Charles Ellicott Commentary 1 Chronicles 4:43

"And they smote the remnant of the Amalekites that escaped, and have dwelt there unto this day." — 1 Chronicles 4:43 (ASV)

The rest of the Amalekites who had escaped. —Literally, the remnant of the survivors (pelêtâh, an abstract collective word) belonging to Amalek. These Amalekites are usually supposed to have been some who had taken refuge in Seir from Saul and David’s exterminating wars (1 Samuel 14:48; 1 Samuel 15:7; 2 Samuel 8:12. Compare to 1 Chronicles 1:36, where Amalek appears as a partly Edomite stock.)