וְיִגְדַּ֨ל שִׁמְךָ֤ עַד־עוֹלָם֙ לֵאמֹ֔ר יְהוָ֣ה צְבָא֔וֹת אֱלֹהִ֖ים עַל־יִשְׂרָאֵ֑ל וּבֵית֙ עַבְדְּךָ֣ דָוִ֔ד יִהְיֶ֥ה נָכ֖וֹן לְפָנֶֽיךָ׃
Damit groß sei dein Name auf ewig, dass man sage: Der Herr Zebaot ist Gott über Israel, und das Haus deines Knechtes David sei gegründet vor dir.
Mishneh Torah, Kings and Wars
The monarchy remains with the House of David forever, as it says, “your throne shall be established forever” (II Samuel 7:16). In contrast, if a king from (any of the other tribes of) Israel is appointed, the monarchy will cease from his House, as it says with regard to Jeraboam, “but not for all the days” (I Kings 11:39).