Reference for Numbers 8:12

וְהַלְוִיִּם֙ יִסְמְכ֣וּ אֶת־יְדֵיהֶ֔ם עַ֖ל רֹ֣אשׁ הַפָּרִ֑ים וַ֠עֲשֵׂה אֶת־הָאֶחָ֨ד חַטָּ֜את וְאֶת־הָאֶחָ֤ד עֹלָה֙ לַֽיהוָ֔ה לְכַפֵּ֖ר עַל־הַלְוִיִּֽם׃

And the Levites shall lay their hands upon the heads of the bullocks; and offer thou the one for a sin-offering, and the other for a burnt-offering, unto the LORD, to make atonement for the Levites.