וַיַּ֨עַן בְּנָיָ֧הוּ בֶן־יְהֽוֹיָדָ֛ע אֶת־הַמֶּ֖לֶךְ וַיֹּ֣אמֶר ׀ אָמֵ֑ן כֵּ֚ן יֹאמַ֣ר יְהוָ֔ה אֱלֹהֵ֖י אֲדֹנִ֥י הַמֶּֽלֶךְ׃
Da rief Benajahu, Sohn Jojadas, dem König zu und sprach: Amen! Also wolle der Gott meines Herrn, des Königs!
Rashi
Amein. [Long] live Shlomo.29“Amein” serves as an affirmation to this proclamation.
Ralbag
Amen! So says the Lord, God of my lord the king: This is a prayer that the will of the Blessed Lord will be that the matter will be so. That is to say that the kingship will be Solomon's, because if it doesn't come to him through God's will, this will be of no use to him.