Once again there was a battle with the Philistines, and Elhanan son of Jair killed Lahmi the brother of Goliath the Gittite, the shaft of whose spear was like a weaver’s beam.
The Philistines were nearly subdued (Ch1 18:1); but, as in the destruction of the Canaanites by Joshua the sons of Anak were last subdued (Jos 11:21), so here in the conquest of the Philistines the giants of Gath were last brought down.
Commenting on 1 Chronicles 20:4-8
And there was war again with the Philistines; and Elhanan the son of Jair slew Lahmi the brother of Goliath the Gittite, whose spear staff [was] like a weaver's beam. (c) Read .
Elhanan the son of Jair - See the note on Sa2 21:19. The Targum says, "David, the son of Jesse, a pious man, who rose at midnight to sing praises to God, slew Lachmi, the brother of Goliath, the same day on which he slew Goliath the Gittite, whose spear-staff was like a weaver's beam."