Leviticus 16:12 Commentary - Ellicott's Commentary for English Readers (Old and New Testaments)

(12) A censer full of burning coals.—After the bullock was slain, and before its blood was sprinkled, the high priest took the censer, which on this occasion was a golden one, and filled it with brightly glowing coals. These he took off from that part of the ever-burning fire on the altar of burnt offering or brazen altar which was next to the west, towards the Holy of Holies, where the Lord had His dwelling. This is the sense which the canonical law attached to the phrase here “before the Lord.”

And his hands full of sweet incense.—Having provided himself with two handfuls of the finest incense, and holding the censer with the fire in his right hand, and the cup with the incense in his left, he now entered for the first time through the second vail into the Holy of Holies, advanced to the ark of the covenant, and deposited the censer between its two staves. During the second Temple he stepped forward to the stone which was the substitute of the Ark, and placed the censer upon it.