Genesis 14:13-14

13Then a soldier who had escaped came and told Abram the Hebrew what had happened. He was living next to the oak trees belonging to Mamre the Amorite, a brother of Eshcol and Aner. (These men were Abram’s allies.)

14When Abram heard that his nephew had been captured, he armed his 318 trained men, born in his own household, and pursued the four kings all the way to Dan.