Numbers 4:20

20 The Kohathites must never enter the sanctuary to look at the sacred objects for even a moment, or they will die.”

Numbers 4:20 Meaning and Commentary

Numbers 4:20

But they shall not go in to see when the holy things are
covered
They were not to be present while they were packing up, test they should see any of them with their eyes; they were not to go in until they were quite covered out of sight; which may signify the hiding of the mysteries of grace in those things under the former dispensation, when even the Levites themselves were not admitted to a sight of them; see ( Ephesians 3:4 Ephesians 3:5 ) ;

lest they die;
by the immediate hand of God.

Numbers 4:20 In-Context

18 “Do not let the Kohathite clans be destroyed from among the Levites!

19 This is what you must do so they will live and not die when they approach the most sacred objects. Aaron and his sons must always go in with them and assign a specific duty or load to each person.

20 The Kohathites must never enter the sanctuary to look at the sacred objects for even a moment, or they will die.”

21 And the LORD said to Moses,

22 “Record the names of the members of the clans and families of the Gershonite division of the tribe of Levi.