Numbers Chapter 21

34The Lord said to Moses, "Do not fear him, for I have delivered him, his people, and his land into your hand. You shall do to him as you did to Sihon the king of the Amorites who dwells in Heshbon.   לדוַיֹּ֨אמֶר יְהֹוָ֤ה אֶל־משֶׁה֙ אַל־תִּירָ֣א אֹת֔וֹ כִּ֣י בְיָֽדְךָ֞ נָתַ֧תִּי אֹת֛וֹ וְאֶת־כָּל־עַמּ֖וֹ וְאֶת־אַרְצ֑וֹ וְעָשִׂ֣יתָ לּ֔וֹ כַּֽאֲשֶׁ֣ר עָשִׂ֗יתָ לְסִיחֹן֙ מֶ֣לֶךְ הָֽאֱמֹרִ֔י אֲשֶׁ֥ר יוֹשֵׁ֖ב בְּחֶשְׁבּֽוֹן:
Do not fear him: Moses was afraid to fight [against him] lest the merit of Abraham advocate for him, as it says, “The refugee came” (Gen. 14:13) -this was Og who had escaped from the Rephaim, who were smitten by Chedorlaomer and his allies at Ashteroth Karnaim, as it says, “only Og, the king of Bashan, was left of the remnant of the Rephaim” (Deut. 3:11). - [Midrash Tanchuma Chukkath 24, Num. Rabbah 19:32]   אל תירא אותו: שהיה משה ירא להלחם, שמא תעמוד לו זכותו של אברהם, שנאמר (בראשית יד, יג) ויבא הפליט, הוא עוג, שפלט מן הרפאים שהכו כדרלעומר וחביריו בעשתרות קרנים, שנאמר (דברים ג, יא) כי רק עוג מלך הבשן נשאר מיתר הרפאים:
35They smote him, his sons and all his people, until there was no survivor, and they took possession of his land.   להוַיַּכּ֨וּ אֹת֤וֹ וְאֶת־בָּנָיו֙ וְאֶת־כָּל־עַמּ֔וֹ עַד־בִּלְתִּ֥י הִשְׁאִֽיר־ל֖וֹ שָׂרִ֑יד וַיִּֽירְשׁ֖וּ אֶת־אַרְצֽוֹ:
They smote him: Moses slew him, as it says in [Tractate] Berachoth, in [the chapter beginning] Haroeh (54b): He uprooted a mountain of three parasangs [intending to throw it at the Israelites and crush them]….   ויכו אותו: משה הרגו, כדאיתא בברכות בהרואה (דף נד ב) עקר טורא בת תלתא פרסי וכו':

Numbers Chapter 22

1The children of Israel journeyed and encamped in the plains of Moab, across the Jordan from Jericho.   אוַיִּסְע֖וּ בְּנֵ֣י יִשְׂרָאֵ֑ל וַיַּֽחֲנוּ֙ בְּעַרְב֣וֹת מוֹאָ֔ב מֵעֵ֖בֶר לְיַרְדֵּ֥ן יְרֵחֽוֹ: