Leviticus 16:2, 12-14

The LORD said to Moses: “ T ell your brother Aaron that he shall not enter at any time into the holy place inside the veil, before the mercy seat which is on the ark, or he will die; for I will appear in the cloud over the mercy seat.

He shall take a firepan full of coals of fire from upon the altar before the LORD and two handfuls of finely ground sweet incense, and bring it inside the veil. He shall put the incense on the fire before the LORD, that the cloud of incense may cover the mercy seat that is on the ark of the testimony, otherwise he will die. Moreover, he shall take some of the blood of the bull and sprinkle it with his finger on the mercy seat on the east side; also in front of the mercy seat he shall sprinkle some of the blood with his finger seven times.