וַאֲנִ֞י הִנֵּ֧ה נְתַתִּ֣יךָ הַיּ֗וֹם לְעִ֨יר מִבְצָ֜ר וּלְעַמּ֥וּד בַּרְזֶ֛ל וּלְחֹמ֥וֹת נְחֹ֖שֶׁת עַל־כָּל־הָאָ֑רֶץ לְמַלְכֵ֤י יְהוּדָה֙ לְשָׂרֶ֔יהָ לְכֹהֲנֶ֖יהָ וּלְעַ֥ם הָאָֽרֶץ׃
至於我，看哪，我今天使你成為堅固城、鐵柱、銅牆，抵擋這全地，就是抵擋猶大的君王、猶大的首領、猶大的祭司和這地的百姓。
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.