בַּיּ֣וֹם הַה֔וּא יוּשַׁ֥ר הַשִּׁיר־הַזֶּ֖ה בְּאֶ֣רֶץ יְהוּדָ֑ה עִ֣יר עָז־לָ֔נוּ יְשׁוּעָ֥ה יָשִׁ֖ית חוֹמ֥וֹת וָחֵֽל׃
In that day shall this song be sung in the land of Judah: We have a strong city; Walls and bulwarks doth He appoint for salvation.
Rashi on Isaiah
The city that was our strength, salvation shall He place The city of Jerusalem, which was always our strength from time immemorial, the Savior shall place salvation for its walls and its bulwark.
Ibn Ezra on Isaiah
עיר עז לנו ישועה ישית To a city which is strength to us,1A. V., We have a strong city. he will appoint salvation. To Jerusalem, which is strength unto us, God will appoint salvation.2After ישית the word ישועה salvation seems to have been omitted in the Hebrew text.