"The Heavenly Sanctuary"
A pastor tells a personal experience regarding the sanctuary in heaven. He says, "Upon entering pastoral duties in a church, I was confronted with a paper written by a scholar who denounced the teaching of the sanctuary in heaven. Three persons each gave me a copy of this paper. I knew that in time I would have to deal publicly with this scholarly paper. The time finally came When I was doing a sermon series dealing with the book of Daniel.
During the week of preparation for the upcoming Sabbath sermon, the Lord impressed my mind with a simple question to ask the congregation. During that sermon, I mentioned to the congregation the following: "If someone tells you there is no sanctuary in heaven, do not argue with him/her. Ask the person the following question: 'Oh, have you been to heaven to see that there is no sanctuary there?'" Next, I said: "If he says 'No,' then you can consider the statement as hearsay." I continued: "The next thing for you to do is to search the Bible about what it says concerning the subject. If it says there is no sanctuary in heaven, then accept it. However, if the Bible says there is a sanctuary in heaven, it will be best to accept that."
You can imagine the brisk activity that simple question caused within the congregation. A few became hostile, while others breathed a sigh of relief when they heard some answers regarding the sanctuary message. Not one who denied the existence of a real sanctuary in heaven could muster an argument against it. At least one who disbelieved in a literal heavenly temple had an about-face and decided to look into the subject from a biblical viewpoint rather than to accept unprovable and negative interpretive assertions." The pastor did not trivialize the Sanctuary doctrine, neither did Ellen G. White.
In The following statements Ellen White tells is how important is the doctrine of the sanctuary,
"The correct understanding of the ministration in the heavenly sanctuary is the foundation of our faith," "our faith" being the unique teachings of Seventh-day Adventists that make us different from the Roman Catholic or Evangelical Protestant churches. 
"[It's] the central pillar that sustains the structure of our position." 
"the sanctuary in heaven is the very center of Christ's work in behalf of men," 
Notice what she has to say about the denial of the heavenly sanctuary by some among us:
The enemy will bring in false theories, such as the doctrine that there is no sanctuary. This is one of the points on which there will be a departing from the faith. 
Satan is striving continually to bring in fanciful suppositions in regard to the sanctuary, degrading the wonderful representations of God and the ministry of Christ for our salvation into something that suits the carnal mind. He removes its presiding power from the hearts of believers, and supplies its place with fantastic theories invented to make void the truths of the atonement, and destroy our confidence in the doctrines which we have held sacred since the third angel's message was first given. Thus he would rob us of our faith in the very message that has made us a separate people, and has given character and power to our work.
If there is no sanctuary in Heaven, then the earthly sanctuary on earth is a shadow of Moses imagination. Also, our understanding of Daniel 8:14 (2,300-day prophecy) is based on a fantasy.
This, then, brings us to the lesson for the week at hand. We will consider two aspects of the heavenly sanctuary ministry. These are its literalness and a few of its functions. While it is true that the functions of the sanctuary are the most critical part of the sanctuary message, the architecture and architectural furnishings are also referred to in several Bible passages. This too is important. Hebrews 8-10 deals with the literalness along with functions of the heavenly temple. Likewise in the book of Revelation which has abundant evidence of a heavenly sanctuary (see 1:12-13; chapters 4 and 5; 8:2-6; 11:19; 15:5). The book of Psalms also mentions the sanctuary or temple and constituent parts over 100 times. And of course, the prophet Daniel wrote concerning the sanctuary in heaven as a place of judgment (Dan 7:-13; 8:14).
The most important elements of the heavenly sanctuary are its functions. One such function is that it is God's dwelling place. However, this brings to mind questions concerning the relationship of God to a dwelling place. Does He need this in light of the fact He is omnipresent (Jer 2: 23-24; Psa 139; Acts 17:24-28)? Since God is ever present in all places at all times, why does He dwell in a temple? In addition to these questions, there is another, how long has there been a temple?
The heavenly sanctuary has been in existence at least since the creation of this world. Jeremiah referred to God's throne and the refuge existing from the point of web time connected to the beginning: "A glorious high throne from the beginning is the place of our sanctuary" (Jer 17:12). Jeremiah's words reflect the farthest point in time for earth which was "in the beginning" when God created earth (Gen 1:1).
The key to the question as to, "why God dwelling in a sanctuary is found in His instruction to Moses: "Let them make Me a sanctuary, that I may dwell among them" (Ex 25:8). God wants to be with us. His name is called "Immanuel" literally meaning "God with us" (Isa 7:14). Our heavenly Father longs to be with His created beings. He wants to interact with us. Jesus revealed God's longing when He was born into the human race to dwell with us as "Immanuel" (Matt 1:23).
Today God also dwells with angels—"between the cherubim" (Psa 80:1; 99:1; Isa 37:16). He longs to be close to His creatures. And the angels love to dwell in the house of the Lord. God also longs for the day when you and I and all the redeemed will be taken to heaven to dwell in His house forever. Jesus went to heaven to prepare "rooms" for us in the "Father's house" (John 14:1-3, NIV), which is the heavenly temple.
Does God need a place to dwell? Of course not. But the fact that He does reveal attributes of His character that are blessings to us by His presence in the Person of the Holy Spirit. In the teacher's comments for this week's lesson there is a thought-provoking statement:
It is vital to grasp that the original purpose of the heavenly sanctuary was to reveal part of the essential nature of God's character—"Immanuel"—God with us. That God condescends to live in a heavenly sanctuary among the created heavenly beings reveals that He is not aloof, distant, cold and forbidding. He longs to be close to His creatures, and to dwell with us. 
Not only is there a temple in heaven - God's dwelling place. In the book of Revelation, the sanctuary is the place of worship for angels and for those who have been redeemed from the earth, (either through translation and resurrection from the grave) (Rev 4:1-11; 5:8-14).
Was there a sanctuary in heaven before sin entered the universe? Yes. Lucifer as the covering cherub was there as a participant in the worship services (Eze 28:17). This was his place of worship until he "desecrated your (his) sanctuaries" (holy places) (v 18, NIV). Then he started a war in heaven, in which he thought he could unseat God from the worship center.
Lucifer attempted to "sit on the mount of the congregation on the farthest sides of the north" (Isa 14:13). The NIV calls this "mount of the congregation" "the mount of assembly." Lucifer wanted to break into God's house of worship which is also His residence.
Lucifer, too late learned that God's temple in heaven is not only His dwelling place and creation's worship place, but that it is also the courtroom where he is judged, condemned and sentenced to eternal death. It is this function of the heavenly sanctuary—the investigative judgment—upon which we Seventh-day Adventists mostly dwell. This we must do, but we must not forget the other above mentioned and very important functions of God's heavenly sanctuary.
In closing, we must consider another vitally important function of the heavenly sanctuary. In Revelation, the Lamb metaphor is the "key" to the sanctuary and to the book. Most of the twenty-eight references to Christ the Lamb occur in worship passages and center on salvation more than judgment. The Lamb fulfills the promise of God to establish righteousness, depicting redemption through Christ's sacrifice on the cross. In Rev 5:6 a slain lamb is seen in the midst of the throne which is located in the heart of the temple. This is a revelation of Christ crucified as the central attraction in the heavenly sanctuary. It reveals the self-sacrificing love and mercy of Christ and the Father and His government. But that is not all.
In Revelation the Lamb of God has two aspects: a sacrificial Lamb and a military Lamb (Rev 5:6; 12:11;13:8; 17:14). They are interconnected, standing in the heart of the book depicting the two sides of God's activity—His mercy and his justice. So we observe the two primary motifs: the sacrificial lamb metaphor united with the metaphorical Lamb Leader, Ruler, and Judge. The two are combined here. Just as God's mercy and His justice meet in the Lamb slain from the foundation of the world. It is the sacrifice of the Lamb that exalts the temple in heaven along with its other functions that we have considered in this lesson—of God's dwelling place and creation's house of worship along with God's judgment.
 Evangelism, p. 221.
 Manuscript Releases, vol. 4, p. 245 (1897).
 Evangelism, p. 222.
 Review and Herald, May 25, 1905.
 Special Testimonies, Series B, No. 7, p. 17. (1905); Counsels to Writers and Editors, p. 53-54.
 Adult Teachers Sabbath School Bible Study Guide, Oct | Nov | Dec 2013, p. 16.