Did you know that God has a sanctuary?
Your way, O God, is in the sanctuary [in holiness, away from sin and guilt]; who is a great God like our God?
Psalms 77:13 AMP.
God's way is in the sanctuary so this must be an important subject to study.
Actually the Bible teaches us about two different sanctuaries, one on the earth, and the other in heaven.
THE EARTHLY
Just after the Israelite exodus from Egypt the Lord desired to give His people an object lesson about the plan of redemption and the office and ministry of the coming Messiah. He instructed Moses
... have them make me a sanctuary, so that I may dwell among them.
Exodus 25:8.
Basically this consisted of a tent structure with two rooms and a fenced courtyard.
When an Israelite sinned, he could bring an offering to the sanctuary. This would be of cattle or sheep or goats or fowls (Leviticus 1:2,10,14). A priesthood was instituted to minister these offerings to the Lord for the people.
The sinner would confess his sin, placing his hand on the victim's head, symbolically transferring his sin to the sacrifice. Leviticus 4:4, 15; Numbers 5:7. The sacrifice was then killed. All these animal sacrifices pointed forwards to Jesus "... the Lamb of God who takes away the sin of the world!" John 1:29. Jesus told His disciples at the last supper "... this is my blood of the covenant, which is poured out for many for the forgiveness of sins." Matthew 26:28. And of the sanctuary service, we are told "... almost everything is purified with blood, and without the shedding of blood there is no forgiveness of sins." Hebrews 9:22.
So the sacrifice had to be killed. The priest would then take some of the victim's blood into the first room of the sanctuary and put some of it upon the horns of the altar of sweet incense before the Lord. Leviticus 4:7, 18.
Sometimes the flesh of the victim was instead to be eaten by the priest. Leviticus 6:30; 10:18. Both actions symbolized the transfer of sin from the sinner to the sanctuary. When this had been done for the sinner, it was said that the priest had made atonement for that person.