Josué 3:5 Commentaire : Rashi

וַיֹּ֧אמֶר יְהוֹשֻׁ֛עַ אֶל־הָעָ֖ם הִתְקַדָּ֑שׁוּ כִּ֣י מָחָ֗ר יַעֲשֶׂ֧ה יְהוָ֛ה בְּקִרְבְּכֶ֖ם נִפְלָאֽוֹת׃

Et Josué dit au peuple: "Sanctifiez-vous! Car, demain, l’Éternel accomplira au milieu de vous des merveilles."

And Yehoshua said. This was on the third day, and the thirtieth day of mourning [for Moshe] was on the first of the three days.

הִתְקַדָשׁוּ usually means sanctify yourselves, but here it means prepare yourselves.

For tomorrow when you cross the Jordan.