כִּֽי־יַכְרִ֞ית יְהוָ֤ה אֱלֹהֶ֙יךָ֙ אֶת־הַגּוֹיִ֔ם אֲשֶׁר֙ יְהוָ֣ה אֱלֹהֶ֔יךָ נֹתֵ֥ן לְךָ֖ אֶת־אַרְצָ֑ם וִֽירִשְׁתָּ֕ם וְיָשַׁבְתָּ֥ בְעָרֵיהֶ֖ם וּבְבָתֵּיהֶֽם׃
When the LORD thy God shall cut off the nations, whose land the LORD thy God giveth thee, and thou dost succeed them, and dwell in their cities, and in their houses;
Sifrei Devarim
(Devarim 19:1) "When the L-rd your G-d cuts off the nations whose land the L-rd your G-d gives to you": in your merit.