He is to put the incense on the fire before the LORD, and the cloud of incense will cover the mercy seat above the Testimony, so that he will not die.

Exodus 25:21
Set the mercy seat atop the ark, and put the Testimony that I will give you into the ark.

Exodus 28:43
Aaron and his sons must wear them whenever they enter the Tent of Meeting or approach the altar to minister in the Holy Place, so that they will not incur guilt and die. This is to be a permanent statute for Aaron and his descendants.

Leviticus 22:9
The priests must keep My charge, lest they bear the guilt and die because they profane it. I am the LORD who sanctifies them.

Numbers 4:15
When Aaron and his sons have finished covering the holy objects and all their equipment, as soon as the camp is ready to move, the Kohathites shall come and do the carrying. But they must not touch the holy objects, or they will die. These are the transportation duties of the Kohathites regarding the Tent of Meeting.

Numbers 4:20
But the Kohathites are not to go in and look at the holy objects, even for a moment, or they will die."

Deuteronomy 33:10
He will teach Your ordinances to Jacob and Your law to Israel; he will set incense before You and whole burnt offerings on Your altar.

And he shall put the incense on the fire before the LORD, that the cloud of the incense may cover the mercy seat that is on the testimony, that he die not: