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.
Read halakhic rulings (Jewish law) on Numbers 8:14: and classical halakhic sources.