TSK · Numbers 1:51

You shall appoint Aaron and his sons, and they shall keep their priesthood. The stranger who comes near shall be put to death."

Yahweh spoke to Moses and to Aaron, saying,

but thus do to them, that they may live, and not die, when they approach to the most holy things: Aaron and his sons shall go in, and appoint them everyone to his service and to his burden;

It happened in the second year, in the second month, on the twentieth day of the month, that the cloud was taken up from over the tabernacle of the testimony.

The Kohathites set forward, bearing the sanctuary. The others set up the tabernacle before they arrived.

It shall happen, that the rod of the man whom I shall choose shall bud: and I will make to cease from me the murmurings of the children of Israel, which they murmur against you."

You and your sons with you shall keep your priesthood for everything of the altar, and for that within the veil; and you shall serve: I give you the priesthood as a service of gift: and the stranger who comes near shall be put to death."

He struck of the men of Beth Shemesh, because they had looked into the ark of Yahweh, he struck of the people fifty thousand seventy men; and the people mourned, because Yahweh had struck the people with a great slaughter.