Exodus 30:8

“In the tent of meeting, outside the veil which is before the testimony, Aaron and his sons shall keep it in order from evening to morning before Yahweh; it shall be a perpetual statute throughout their generations for the sons of Israel.

as a memorial to the sons of Israel that no outsider who is not of the seed of Aaron should come near to burn incense before Yahweh; so that he will not become like Korah and his congregation—just as Yahweh had spoken to him by the hand of Moses.

‘And did I not choose them from all the tribes of Israel to be My priests, to go up to My altar, to burn incense, to carry an ephod before Me; and did I not give to the house of your father all the fire offerings of the sons of Israel?

The sons of Amram were Aaron and Moses. And Aaron was separated in order to sanctify him as most holy, he and his sons forever, to offer offerings up in smoke before Yahweh, to minister to Him and to bless in His name forever.

and for the altar of incense refined gold by weight; and gold for the pattern of the chariot, even the cherubim that spread out their wings and covered the ark of the covenant of Yahweh.

And they stood against Uzziah the king and said to him, “It is not for you, Uzziah, to burn incense to Yahweh, but for the priests, the sons of Aaron who are set apart as holy to burn incense. Get out of the sanctuary, for you have been unfaithful and will have no honor from Yahweh God.”

May my prayer be established as incense before You; The lifting up of my hands as the evening offering.

according to the custom of the priestly office, he was chosen by lot to enter the sanctuary of the Lord and burn incense.