"Q: What is meant by the cleansing of the sanctuary?
And as we live at a time when the 2300 days/years are in the past, we are most deeply concerned to understand the nature of the work called the cleansing of the sanctuary.
The Bible is full of the subject of the sanctuary, and we shall find it a theme of intense interest if we give it careful study. The Bible doctrine of the sanctuary is this:
---That the sanctuary is the place where the High Priest stands to offer blood before God for the sins of those who come to God 
through him.
---The central subject in the sanctuary is the ark which contains the law of God that man has broken.
---The cover of this ark was called the mercy-seat, because mercy came to those who had broken the law beneath it, when the high priest sprinkled the blood of sin-offering upon it, provided they accompanied his work by repentance and faith.
---Last of all was the work of cleansing the sanctuary when the high priest by blood removed the sins of the people from the sanctuary into which they had been borne by the ministration of the priests before God.
We now invite attention to the testimony of the Bible respecting the sanctuary.
1. There are two covenants; the first, or old covenant, extends from the time of Moses to the death of Christ; the second, or new covenant, begins at the death of Christ and extends forward to the consummation. Gal.4:24-26; Heb.8:7-13; Luke 22:20.
2. The first covenant had a sanctuary, which was the tabernacle erected by Moses. Heb.9:1-7. 3.
The new covenant has a sanctuary which is the temple of God in Heaven, into which our High Priest entered when he ascended up on high. Heb.8:1-5. 4.
When Moses erected the tabernacle, he was commanded by God to make it according to the pattern which he showed to him; and this pattern must have been a representation of the temple of God in Heaven; for the earthly sanctuary is declared to be a pattern of the heavenly. Ex.25:9,40; Heb.8:5; 9:23.5.
The earthly sanctuary consisted of two holy places;
---the first of which contained the table of shew-bread, the candlestick with seven lamps, and the golden altar of incense; and ---the second contained the ark of God’s testament with the tables on which the ten commandments were written by the finger of God, and over which was the mercy-seat with the cherubim of glory overshadowing it. Ex.40:18-28; Heb.9:1-5.6.
The temple of God in Heaven is not only spoken of as the original from which the earthly sanctuary was copied (Heb.9:23,24; 1Chron.28:11,12,19), but it is also spoken of as consisting of holy places, in the plural. See Heb.8:2; 9:8,12,24;10:19, in each of which verses the original is holy places, in the plural, and they are so rendered in various translations.
*-*The ministration in the earthly sanctuary could not actually take away sins; for it had only the blood of bulls and goats to offer. Heb.10:4.
--It was ordained for the purpose of instructing men with reference to the work of Christ, and of encouraging them to look forward to His work.
It is a shadow or representation of the service of Christ in the sanctuary of God in Heaven. Heb.8:5; 10:1; Col.2:17.
It took one year to complete the round of service in the earthly sanctuary, at the end of which the cleansing of the sanctuary took place. The round of service was repeated each year, even as a shadow is renewed each day.
But the ministration of Christ which casts this shadow fills out each part of the work once for all, and is not repeated. We shall therefore find the study of the service in the earthly sanctuary full of instruction as to the work of Christ in the sanctuary above.
The ministration in the first apartment occupied the entire year, with the exception of one day, which was devoted to work in the second apartment, or most holy place, to close up the work which had been wrought in the first apartment.
The work in the first apartment was on this wise:
--When a man repented of his sin, he brought a sin-offering to the priest to the door of the sanctuary.
--Then he confessed his sin to the priest and put his hand upon the head of his offering to indicate the transfer of the guilt from himself to his offering.
--Then, the victim was slain because of that guilt thus transferred to it, and the blood, representing the life of the victim, was taken by the priest and carried into the sanctuary, and sprinkled there before God.
On the tenth day of the seventh month,
which was called the day of atonement, the ministration was transferred to the second apartment, or most holy place. Lev.16.
--By God’s direction, the high priest on this day caused two goats to be brought to the door of the sanctuary.
--On these he was to cast lots.
One was for the Lord,
the other was for Azazel.
--Then he slew the goat upon which the Lord’s lot fell, and took his blood to present it before God as a sin-offering in the most holy place, sprinkling it upon the mercy-seat.
--He did this for two purposes:
1. To make atonement for the people.
2. To cleanse the sanctuary by removing from it the sins of the people of God. Lev.16:15-19.
--The sanctuary being cleansed, the high priest comes out of the building, and having caused the other goat to be brought which was for Azazel, he lays both his hands upon his head, and confesses over him all the transgressions of the children of Israel in all their sins. These he puts upon the head of the goat and sends him away by the hand of a fit man into the wilderness. And it is said that “the goat shall bear upon him all their iniquities unto a land not inhabited.” Verses 20-22.
--The sanctuary being cleansed, the high priest comes out of the building, and having caused the other goat to be brought which was for Azazel, he lays both his hands upon his head, and confesses over him all the transgressions of the children of Israel in all their sins. These he puts upon the head of the goat and sends him away by the hand of a fit man into the wilderness. And it is said that “the goat shall bear upon him all their iniquities unto a land not inhabited.” Verses 20-22.
*The work of the high priest on this great day of atonement was for the purpose of completing the work which had been partially accomplished in the first apartment. 
*By the work in that apartment, the sins had been transferred to the sanctuary through the blood of sin-offering.
*By the work in the second apartment, the sanctuary is cleansed and the sins of the people of God blotted out.
Such was the work in the earthly sanctuary, and such was the cleansing of the sanctuary as set forth in the example and shadow of heavenly things. The earthly sanctuary was only made as the pattern of the sanctuary in Heaven. Heb.8 and 9."
J.N. Andrews