וְאַתָּ֤ה קַח־לְךָ֙ מַחֲבַ֣ת בַּרְזֶ֔ל וְנָתַתָּ֤ה אוֹתָהּ֙ קִ֣יר בַּרְזֶ֔ל בֵּינְךָ֖ וּבֵ֣ין הָעִ֑יר וַהֲכִינֹתָה֩ אֶת־פָּנֶ֨יךָ אֵלֶ֜יהָ וְהָיְתָ֤ה בַמָּצוֹר֙ וְצַרְתָּ֣ עָלֶ֔יהָ א֥וֹת הִ֖יא לְבֵ֥ית יִשְׂרָאֵֽל׃ (ס)
At ikaw, kumuha ka ng isang kawaling bakal, at ilagay mo ito bilang pader na bakal sa pagitan mo at ng lungsod; ituon mo ang iyong mukha laban dito, at ito ay mapapasailalim sa pagkubkob, at kukubkubin mo ito. Ito ay isang tanda para sa sambahayan ng Israel.
Rashi
an iron wall A semblance of the city wall that serves as a partition between the army and the city.
Rashi
that is a sign that so will Jerusalem come under siege.