Genesis 14:13-14

13Then a survivor who had escaped [from the invading forces on the other side of the Jordan] came and told Abram the Hebrew. Now he was living by the terebinths (oaks) of Mamre the Amorite, brother of Eshcol and brother of Aner—they were allies of Abram.

14When Abram heard that his nephew [Lot] had been captured, he armed and led out his trained men, born in his own house, [numbering] three hundred and eighteen, and went in pursuit as far [north] as Dan.