Jambri

JAMBRI jăm’ brī (̓Ιαμβρί). The name of a tribe that came out of Medeba (mentioned in Num 21:31 as a city of the Amorites) and took captive John, the brother of Jonathan, the Maccabean leader of the Jews, and seized everything that he possessed. This outrage was avenged by his brothers, Jonathan and Simon, who ambushed a wedding party of the sons of Jambri, killing many, and taking their spoils (1 Macc 9:36).

International Standard Bible Encyclopedia (1915)

The sons of Jambri are said to have come out of Medeba (originally Med’ba), a city of the Moabites, and subsequently a possession of the Amorites, and to have carried off John, the brother of Jonathan, who succeeded Judas Maccabeus as leader of the Jews. The Israelites got possession of the place and assigned it to the tribe of Reuben. No mention is made elsewhere of the Jambri. In Josephus (Ant., XIII, i, 2) they are called "sons of Amaraeus."