זֹ֛את עֲבֹדַ֥ת בְּנֵי־קְהָ֖ת בְּאֹ֣הֶל מוֹעֵ֑ד קֹ֖דֶשׁ הַקֳּדָשִֽׁים׃
This is the service of the sons of Kohath in the tent of meeting, about the most holy things:
Read kabbalistic (mystical) interpretation of Numbers 4:4: and classical mystical sources.