מַגִּישִׁ֤ים עַֽל־מִזְבְּחִי֙ לֶ֣חֶם מְגֹאָ֔ל וַאֲמַרְתֶּ֖ם בַּמֶּ֣ה גֵֽאַלְנ֑וּךָ בֶּאֱמָרְכֶ֕ם שֻׁלְחַ֥ן יְהוָ֖ה נִבְזֶ֥ה הֽוּא׃
Ye offer polluted bread upon Mine altar. And ye say: ‘Wherein have we polluted thee?’ In that ye say: ‘The table of the LORD is contemptible.’
Read midrashic interpretation of Malachi 1:7: and classical rabbinic exegesis.