Numbers 3:9 Kabbalah

וְנָתַתָּה֙ אֶת־הַלְוִיִּ֔ם לְאַהֲרֹ֖ן וּלְבָנָ֑יו נְתוּנִ֨ם נְתוּנִ֥ם הֵ֙מָּה֙ ל֔וֹ מֵאֵ֖ת בְּנֵ֥י יִשְׂרָאֵֽל׃

And thou shalt give the Levites unto Aaron and to his sons; they are wholly given unto him from the children of Israel.

Read kabbalistic (mystical) interpretation of Numbers 3:9: and classical mystical sources.