Kommentar zu Bereschit 14:13

ויבא הפליט AND THERE CAME THE ONE WHO ESCAPED — According to the real meaning this was Og who had escaped from the battle with the Rephaim (see Genesis 5:5) and it is to this that the text refers (Deuteronomy 3:11) “For only Og king of Bashan was left of the remnant of the Rephaim”, and this is what is meant by נשאר “left”, for Amraphel and his allies did not kill him when they smote the Rephaim in Ashteroth Karnaim. So is the statement in the Tanchuma 4:6:25 (Chukat). But according to the Midrash Genesis Rabbah (Genesis Rabbah 42:8) it refers to Og in allusion to him as the only one of the generation of the Flood who escaped that catastrophe, and this is what is meant (Deuteronomy 3:11) “of the remnant of the Rephaim”, for it is said. (Genesis 6:4) “The Nephilim (= Rephaim cf. Genesis Rabbah 26) were in the earth etc.” His intention in telling Abraham that his nephew was captured was that Abraham should wage war against the kings and that he should be killed so that he, himself, might marry Sarah.

ויגד 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.

ויבא הפליט, after that individual had escaped from captivity he came and told Avram that his nephew had been taken captive, also.