וַיַּ֨עַשׂ הַמֶּ֤לֶךְ רְחַבְעָם֙ תַּחְתֵּיהֶ֔ם מָגִנֵּ֖י נְחֹ֑שֶׁת וְהִפְקִ֗יד עַל־יַד֙ שָׂרֵ֣י הָרָצִ֔ים הַשֹּׁ֣מְרִ֔ים פֶּ֖תַח בֵּ֥ית הַמֶּֽלֶךְ׃
And king Rehoboam made in their stead shields of brass, and committed them to the hands of the captains of the guard, that kept the door of the king’s house.
Read midrashic interpretation of II Chronicles 12:10: and classical rabbinic exegesis.