Who was Abiezer?
(1) Abiezer was a descendant of Joseph the son of Jacob, and head of one of the families of Manasseh that settled West of the Jordan (Nu 26:30; Josh 17:1-6; 1 Ch 7:14-19). As he was great uncle to Zelophehad's daughters, who brought a case before Moses (Nu 36), he must have been an old man at the time of the conquest.
He was the son of Gilead the son of Machir, in the sense of being a more remote descendant, for Machir had sons before the death of Joseph (Gen 50:23). The Machir that possessed Gilead and Bashan because he was "a man of war" was the Manassite family of Machir, with Jair as its great general (Josh 17:1; 13:30,31; Nu 32:39-41; Dt 3:12-15). To Abiezer and other sons of Gilead territory was assigned West of the Jordan.
In later generations the name survived as that of the family to which Gideon belonged, and perhaps also of the region which they occupied (Jdg 6:34; 8:2). They are also called Abiezrites (Jdg 6:11,24; 8:32). The region was West of Shechem, with Ophrah for its principal city.
(2) One of David's mighty men, "the Anathothite" (2 Sam 23:27; 1 Ch 11:28), who was also one of David s month-by-month captains, his month being the ninth (1 Ch 27:12).
IBSE, "Isaac" (in the public domain) with minor edits.