עַ֠ד אֲשֶׁר־יָנִ֨יחַ יְהוָ֥ה ׀ לַֽאֲחֵיכֶם֮ כָּכֶם֒ וְיָרְשׁ֣וּ גַם־הֵ֔ם אֶת־הָאָ֕רֶץ אֲשֶׁ֨ר יְהוָ֧ה אֱלֹהֵיכֶ֛ם נֹתֵ֥ן לָהֶ֖ם בְּעֵ֣בֶר הַיַּרְדֵּ֑ן וְשַׁבְתֶּ֗ם אִ֚ישׁ לִֽירֻשָּׁת֔וֹ אֲשֶׁ֥ר נָתַ֖תִּי לָכֶֽם׃
пока Господь не даст покоя вашим братьям, как вам, и они также овладеют землей, которую Господь, Бог ваш, дает им за Иорданом; тогда вы вернете каждого человека в его владение, которое Я вам дал.
Rashbam
והניחותי לך, My presence will remain with you until I have brought you to settlement after you have conquered the land of Canaan and you have rest from all your enemies. Moses had confirmed this promise in Deuteronomy 3,20 as well as in Deuteronomy 25,19, the wording being unmistakable והיה בהניח ה' לכם מכל אויביך מסביב, “it will be when the Lord will give you rest from all your enemies surrounding you, etc.” Anyone who translates the words והניחותי לך as G’d telling Moses that He will put his mind at rest by agreeing to his request is in error. If that could be the meaning, we would have to ask why only in this instance did G’d use such language when on the many other occasions G’d agreed to a request by Moses He never added the words: “so as to put your mind at rest?”