וּשְׁמַרְתֶּ֗ם אֵ֚ת מִשְׁמֶ֣רֶת הַקֹּ֔דֶשׁ וְאֵ֖ת מִשְׁמֶ֣רֶת הַמִּזְבֵּ֑חַ וְלֹֽא־יִהְיֶ֥ה ע֛וֹד קֶ֖צֶף עַל־בְּנֵ֥י יִשְׂרָאֵֽל׃
And ye shall keep the charge of the holy things, and the charge of the altar, that there be wrath no more upon the children of Israel.
Read kabbalistic (mystical) interpretation of Numbers 18:5: and classical mystical sources.