Genesis 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. העברי THE HEBREW — the one who came from the other side (עבר) of the River (Euphrates) (Genesis Rabbah 42:8). בעלי ברית אברם CONFEDERATE WITH ABRAM (literally, owners of a covenant with Abram) — They had entered into a covenant with him. Other versions of Rashi have: another explanation is, they advised him to circumcise himself (to keep the [ברית] covenant), as is explained in another place (cf. Rashi on Genesis 18:1).

וַיָּבֹא֙ הַפָּלִ֔יט וַיַּגֵּ֖ד לְאַבְרָ֣ם הָעִבְרִ֑י וְהוּא֩ שֹׁכֵ֨ן בְּאֵֽלֹנֵ֜י מַמְרֵ֣א הָאֱמֹרִ֗י אֲחִ֤י אֶשְׁכֹּל֙ וַאֲחִ֣י עָנֵ֔ר וְהֵ֖ם בַּעֲלֵ֥י בְרִית־אַבְרָֽם׃

And there came one that had escaped, and told Avram the Hebrew; for he dwelt by the terebinths of Mamre the Emori, brother of Eshkol, and brother of ῾Aner: and these were confederate with Avram.