וַיֹּ֨אמֶר דָּוִ֜יד לִשְׁלֹמֹ֣ה בְנ֗וֹ חֲזַ֤ק וֶאֱמַץ֙ וַעֲשֵׂ֔ה אַל־תִּירָ֖א וְאַל־תֵּחָ֑ת כִּי֩ יְהוָ֨ה אֱלֹהִ֤ים אֱלֹהַי֙ עִמָּ֔ךְ לֹ֤א יַרְפְּךָ֙ וְלֹ֣א יַֽעַזְבֶ֔ךָּ עַד־לִכְל֕וֹת כָּל־מְלֶ֖אכֶת עֲבוֹדַ֥ת בֵּית־יְהוָֽה׃
Rashi on I Chronicles
Be strong and of good courage in order that your kingdom endure as the Holy One, blessed be He, has promised you, (verse 7): “... and I shall prepare his kingdom to eternity if he strengthens himself to perform My commandments, etc.”