Sforno on Genesis 14:13/ספורנו על בראשית י״ד:י״ג

1ויגד לאברם העברי, this refugee had no idea that Lot was related to Avram. He only knew that Lot’s religious beliefs were similar to those of Avram.

2והוא שוכן באלוני ממרא, this is why Aner, Eshkol, and Mamre participated in the war with Avram, and why he insisted in verse 24 that they receive their share of the loot.