One of the three Amorite lords of the hill-country of western Palestine confederate with Abram (Gen. xiv. 13). When a fugitive announced the plunder of Sodom and Gomorrah by the kings of the east, Abram with the confederatelords, Mamre, Eshcol, and Aner, pursued and overtook the victorious army, and brought back the booty and the captives, among whom were Lot and his family (Gen. xiv. 16). It is noteworthy that Mamre is an early name for Hebron (Gen. xxiii. 19), that Eshcol was at a later time the name of a valley near Hebron (Num. xiii. 23, 24; Deut. i. 24), and that the original reading for Aner (Septuagint 'Aυνάν) may have been, as Cheyne suggests, Enau, a name which may refer to one of the six springs near Hebron.
The Midrash, when treating of Aner (Gen. xviii. 1), states that, although an ally of Abraham and therefore a worthy man, yet he advised the latter against undergoing circumcision, saying: "Wilt thou, an old man of a hundred years, expose thyself to such pain?" Therefore, the angels, when visiting Abraham, avoided the domain of Aner, and sought Abraham while he was dwelling in the territory of Mamre, because the latter, unlike his elder brother, Aner, had said to Abraham: "It would be wrong to disobey the God who hath saved thee from the furnace [into which Nimrod had thrown him (see Abraham, in midrashic literature)], from the kings, and from famine" (Gen. R. xlii. 8).