וַאֲנִ֞י הִנֵּ֧ה נְתַתִּ֣יךָ הַיּ֗וֹם לְעִ֨יר מִבְצָ֜ר וּלְעַמּ֥וּד בַּרְזֶ֛ל וּלְחֹמ֥וֹת נְחֹ֖שֶׁת עַל־כָּל־הָאָ֑רֶץ לְמַלְכֵ֤י יְהוּדָה֙ לְשָׂרֶ֔יהָ לְכֹהֲנֶ֖יהָ וּלְעַ֥ם הָאָֽרֶץ׃
“Adapun Aku, sesungguhnya pada hari ini Aku telah menjadikan engkau kota berkubu, tiang besi, dan tembok-tembok tembaga terhadap seluruh negeri ini, terhadap raja-raja Yehuda, para pemukanya, para imamnya, dan rakyat negeri itu.”
Rashi
Will iron break iron from the north I say that iron that comes from the north is harder than other iron, and this is its interpretation: They were compared to iron (above 6:28), “Going tale bearing like copper and iron.” And concerning Jeremiah it is stated (above 1:18): “I have made you... into an iron pillar and into copper walls,” and his is stronger than theirs, for Nebuchadnezzar will come upon them according to his words.