וְלָקַחְתָּ֣ אֶת־הֶֽחָזֶ֗ה מֵאֵ֤יל הַמִּלֻּאִים֙ אֲשֶׁ֣ר לְאַהֲרֹ֔ן וְהֵנַפְתָּ֥ אֹת֛וֹ תְּנוּפָ֖ה לִפְנֵ֣י יְהוָ֑ה וְהָיָ֥ה לְךָ֖ לְמָנָֽה׃
And thou shalt take the breast of Aaron’s ram of consecration, and wave it for a wave-offering before the LORD; and it shall be thy portion.
Read kabbalistic (mystical) interpretation of Exodus 29:26: and classical mystical sources.