Reference for Numbers 8:14

וְהִבְדַּלְתָּ֙ אֶת־הַלְוִיִּ֔ם מִתּ֖וֹךְ בְּנֵ֣י יִשְׂרָאֵ֑ל וְהָ֥יוּ לִ֖י הַלְוִיִּֽם׃

Thus shalt thou separate the Levites from among the children of Israel; and the Levites shall be Mine.

BDB