Devarim 32:8

בהנחל עליון גוים WHEN THE MOST HIGH DIVIDED TO THE NATIONS THEIR INHERITANCE — when the Holy One, blessed be He gave those who provoked Him to anger their inheritance, He afterwards caused the flood to pass over them and He drowned them (Sifrei Devarim 311:1) בהפרידו בני אדם WHEN HE SEPARATED THE SONS OF ADAM — i.e. when He scattered the generation which witnessed the separation of races, He also had the power to remove them from the world, yet He did not do so, but יצב גבלת עמים HE FIRMLY ESTABLISHED THE BOUNDARIES OF THE NATIONS — He let them (the peoples) remain in existence and did not destroy them, למספר בני ישראל ACCORDING TO THE NUMBER OF THE CHILDREN OF ISRAEL — i.e. because of the number of the children of Israel that were in future to descend from Shem’s sons, and in accordance with the number of seventy souls of the children of Israel who went down to Egypt He firmly established גבלת עמים THE NATIONS ACCORDING TO THEIR BOUNDARIES — i.e. seventy separate nations (cf. Sifrei Devarim 311:5).

When the most High divided to the nations their inheritance, when he separated the sons of Adam, he set the bounds of the people according to the number of the children of Yisra᾽el.

בְּהַנְחֵ֤ל עֶלְיוֹן֙ גּוֹיִ֔ם        בְּהַפְרִיד֖וֹ בְּנֵ֣י אָדָ֑ם יַצֵּב֙ גְּבֻלֹ֣ת עַמִּ֔ים        לְמִסְפַּ֖ר בְּנֵ֥י יִשְׂרָאֵֽל׃