Numbers 33:51

כי אתם עברים את הירדן וגו׳ והורשתם וגו׳ WHEN YOU ARE PASSED OVER THE JORDAN … YOU SHALL DRIVE OUT [ALL THE INHABITANTS] — But had they not already been admonished about this several times? But it is repeated here in this form “when you are passing over the Jordan”, and not as usual “when you come into the land” because Moses spoke thus to them: While you are passing through the Jordan on dry land, you shall pass over having this in view (that you will drive out the inhabitants), and if you do not, the waters will come and overwhelm you. And so indeed we find (Jos. 4:10) that Joshua spoke to them while they were still standing in the Jordan (Sotah 34a).

דַּבֵּר֙ אֶל־בְּנֵ֣י יִשְׂרָאֵ֔ל וְאָמַרְתָּ֖ אֲלֵהֶ֑ם כִּ֥י אַתֶּ֛ם עֹבְרִ֥ים אֶת־הַיַּרְדֵּ֖ן אֶל־אֶ֥רֶץ כְּנָֽעַן׃

Speak to the children of Yisra᾽el, and say to them, When you pass over the Yarden into the land of Kena῾an;