וְשָׁמְר֣וּ אֶת־מִשְׁמַרְתּ֗וֹ וְאֶת־מִשְׁמֶ֙רֶת֙ כָּל־הָ֣עֵדָ֔ה לִפְנֵ֖י אֹ֣הֶל מוֹעֵ֑ד לַעֲבֹ֖ד אֶת־עֲבֹדַ֥ת הַמִּשְׁכָּֽן׃
And they shall keep his charge, and the charge of the whole congregation before the tent of meeting, to do the service of the tabernacle.
Read kabbalistic (mystical) interpretation of Numbers 3:7: and classical mystical sources.