Numbers 4:20
but they shall not go in to see the sanctuary even for a moment, lest they die.”
World English Bible (Public Domain)
In context
Before · Numbers 4:18–19
18“Don’t cut off the tribe of the families of the Kohathites from among the Levites; 19but do this to them, that they may live, and not die, when they approach the most holy things: Aaron and his sons shall go in and appoint everyone to his service and to his burden;
20but they shall not go in to see the sanctuary even for a moment, lest they die.”