The LORD spoke to Moses after two of Aaron's sons had died. They were the sons who died when they came near the Lord.
References for Leviticus 16:1
The LORD said to Moses, "Speak to your brother Aaron. Tell him not to come into the Most Holy Room just anytime he wants to. Tell him not to come behind the curtain that is in front of the cover of the ark. The cover is the place where sin is paid for. If he comes behind the curtain, he will die. That is because I appear in the cloud over the cover.
"Aaron must not enter the area of the sacred tent without bringing a sacrifice. He must bring a young bull for a sin offering. He must also bring a ram for a burnt offering.
"He must put on the sacred inner robe that is made out of linen. He must wear linen underwear next to his body. He must tie the linen belt around him. And he must put on the linen turban. Those are sacred clothes. So he must take a bath before he puts them on.
"The community of Israel must give him two male goats and a ram. The goats are for a sin offering. The ram is for a burnt offering.
"Aaron must offer the bull for his own sin offering. It will pay for his own sin and the sin of his whole family.
"Then he must take the two goats and bring them to me at the entrance to the Tent of Meeting.
He must cast lots for the two goats. One lot is for me. The other is for the goat that carries the people's sins away.
Aaron must bring the goat that is chosen for me by lot. He must sacrifice it for a sin offering.
"But the goat that is chosen by the other lot must remain alive. First it must be brought in to me to pay for the people's sin. Then it must be sent into the desert as a goat that carries the people's sins away.
"Aaron must bring the bull for his own sin offering. It will pay for his own sin and the sin of his whole family. He must kill the bull for his own sin offering.
"He must take a shallow cup full of burning coals from the altar in my sight. He must get two handfuls of incense that is completely ground up. The incense must smell sweet. He must take the cup and the incense behind the curtain.
He must put the incense on the fire in my sight. The smoke from the incense will hide the cover of the ark where the tablets of the covenant are kept. The cover is the place where sin is paid for. Aaron must burn the incense so that he will not die.
"He must dip his finger in the bull's blood. He must sprinkle it on the front of the cover of the ark. He must sprinkle some in front of the cover. He must do it seven times.
"Then Aaron must kill the goat for the sin offering for the people. He must take its blood behind the curtain. There he must do the same thing with it as he did with the bull's blood. He must sprinkle it on the cover of the ark. He must also sprinkle some in front of it.
"That is how he will make the Most Holy Room pure. He must do it because the people of Israel are not 'clean.' They have not obeyed me. They have also committed other sins. Aaron must do the same for the Tent of Meeting because it stands in the middle of the camp. And the camp is not 'clean.'
"No one can be in the Tent of Meeting when Aaron goes into the Most Holy Room to pay for the people's sin. No one can enter the tent until Aaron comes out. He will not come out until he has paid for his own sin and the sin of his whole family. He will not come out until he has also paid for the sin of the whole community of Israel.
"Then he will come out to the altar for burnt offerings. It is in front of the tent where the ark of the LORD is. He will make the altar pure and clean. He will take some of the bull's blood and some of the goat's blood. Then he will put the blood on all of the horns that stick out from the upper four corners of the altar.
He will sprinkle some of the blood on it with his finger seven times. He will do it to make the altar pure. He will do it to set it apart from the people of Israel. They are not 'clean.'
"Aaron will finish making the Most Holy Room pure and clean. He will finish making the Tent of Meeting and the altar pure. "Then he will bring the live goat out.
He must place both of his hands on its head. While he does that, he must tell me about all of the sins the people of Israel have committed. He must tell me about all of their evil acts and the times they did not obey me. In that way he puts their sins on the goat's head. "Then he will send the goat away into the desert. The goat will be led away by a man who was appointed to do it.
The goat will carry all of their sins on itself to a place where there are no people. And the man will set the goat free in the desert.
"Then Aaron must go into the Tent of Meeting. He must take off the linen clothes he put on before he entered the Most Holy Room. He must leave them there.
He must take a bath in a holy place. And he must put on his regular clothes. "Then he will come out and sacrifice the burnt offering for himself. He will also sacrifice the burnt offering for the people. That will pay for his own sin and the people's sin.
He will also burn the fat of the sin offering on the altar.
"The man who sets free the goat that carries the people's sins away must wash his clothes. He must take a bath. After that, he can come back into the camp.
"The bull and the goat for the sin offerings must be taken outside the camp. Their blood was brought into the Most Holy Room. It paid for sin. The hides, meat and guts must be burned up.
"The man who burns them must wash his clothes. He must take a bath. After that, he can come back into the camp.
"Here is a law for you that will last for all time to come. On the tenth day of the seventh month you must not eat anything. You must not do any work. It does not matter whether you are Israelites or outsiders.
"On that day your sin will be paid for. You will be made pure and clean. You will be clean from all of your sins in my sight.
That day is a sabbath for you. You must rest on it. You must not eat anything on that day. That is a law that will last for all time to come.
"The high priest must pay for sin. He must make everything pure and clean. He has been anointed and prepared to become the next high priest after his father. He must put on the sacred clothes that are made out of linen.
He must make the Most Holy Room, the Tent of Meeting and the altar pure. And he must pay for the sin of the priests and all of the people in the whole community.
"Here is a law for you that will last for all time to come. Once a year you must pay for all of the sin of the people of Israel." So it was done, just as the LORD commanded Moses.