בַּיָּמִ֤ים הָהֵם֙ תִּוָּשַׁ֣ע יְהוּדָ֔ה וִירוּשָׁלִַ֖ם תִּשְׁכּ֣וֹן לָבֶ֑טַח וְזֶ֥ה אֲשֶׁר־יִקְרָא־לָ֖הּ יְהוָ֥ה ׀ צִדְקֵֽנוּ׃ (ס)
In those days shall Judah be saved, And Jerusalem shall dwell safely; And this is the name whereby she shall be called, The LORD is our righteousness.
Metzudat David on Jeremiah
and this is the name that He shall call it – This is the name which God will call Jerusalem:
Metzudat David on Jeremiah
the Lord is our righteousness – God will make us righteous when she (Jerusalem) is reestablished.