וּנְתַתִּ֜יךָ לָעָ֣ם הַזֶּ֗ה לְחוֹמַ֤ת נְחֹ֙שֶׁת֙ בְּצוּרָ֔ה וְנִלְחֲמ֥וּ אֵלֶ֖יךָ וְלֹא־י֣וּכְלוּ לָ֑ךְ כִּֽי־אִתְּךָ֥ אֲנִ֛י לְהוֹשִֽׁיעֲךָ֥ וּלְהַצִּילֶ֖ךָ נְאֻם־יְהוָֽה׃
And I will make thee unto this people a fortified brazen wall; And they shall fight against thee, But they shall not prevail against thee; For I am with thee to save thee and to deliver thee, Saith the LORD.
Read midrashic interpretation of Jeremiah 15:20: and classical rabbinic exegesis.