Devarim (Deuteronomy) Chapter 31

4And the Lord will do to them, as He did to the Amorite kings, Sihon and Og, and to their land, [all of] which He destroyed.   דוְעָשָׂ֤ה יְהֹוָה֙ לָהֶ֔ם כַּֽאֲשֶׁ֣ר עָשָׂ֗ה לְסִיח֥וֹן וּלְע֛וֹג מַלְכֵ֥י הָֽאֱמֹרִ֖י וּלְאַרְצָ֑ם אֲשֶׁ֥ר הִשְׁמִ֖יד אֹתָֽם:
5And [when] the Lord delivers them before you, you shall do to them according to all the commandment that I have commanded you.   הוּנְתָנָ֥ם יְהֹוָ֖ה לִפְנֵיכֶ֑ם וַֽעֲשִׂיתֶ֣ם לָהֶ֔ם כְּכָ֨ל־הַמִּצְוָ֔ה אֲשֶׁ֥ר צִוִּ֖יתִי אֶתְכֶֽם:
6Be strong and courageous! Neither fear, nor be dismayed of them, for the Lord, your God He is the One Who goes with you. He will neither fail you, nor forsake you."   וחִזְק֣וּ וְאִמְצ֔וּ אַל־תִּֽירְא֥וּ וְאַל־תַּֽעַרְצ֖וּ מִפְּנֵיהֶ֑ם כִּ֣י | יְהֹוָ֣ה אֱלֹהֶ֗יךָ ה֚וּא הַֽהֹלֵ֣ךְ עִמָּ֔ךְ לֹ֥א יַרְפְּךָ֖ וְלֹ֥א יַֽעַזְבֶֽךָּ:
He will neither fail you: Heb. לֹא יַרְפְּךָ. [The word יַרְפְּךָ stems from the root רפה, meaning “weak.” Thus, the expression here means:] God will not give you [cause for] weakness [resulting] from your being forsaken by Him.   לֹא יַרְפְּךָ: לֹא יִתֵּן לְךָ רִפְיוֹן לִהְיוֹת נֶעֱזָב מִמֶּנּוּ: