Some early Adventists, basing their definition of the term on its OT meaning with reference to the ancient sanctuary service, and believing that the ancient priests served "unto the example and shadow of heavenly things" (Heb. 8:5), stressed this high-priestly aspect of Christ's atoning ministry to the point of seeming to deny that His sacrifice on the cross could properly be called a work of atonement. William Miller, for instance, wrote that Christ's shedding of His blood on Calvary for a sinful world was "the propitiatory sacrifice to God," but that the atonement "is made by his life and intercession in heaven (Heb. 7:25)," "so that through his intercession we can be saved by his life (Rom. 5:10; 1 John 5:11)" (letter of Nov. 22, 1844, in Western Midnight Cry 4:26, Dec. 21, 1844).
The misunderstanding arising from the denial by Miller and by some early SDA writers that atonement was made on the cross is a matter of semantics. None of those who denied this denied either the fact or the efficacy of Christ's sacrifice made on the cross, nor did they believe that He offered another sacrifice in heaven. They were simply using the word "atonement" in its original, biblical sense rather than in the popular theological sense. They pointed out that in the ancient sanctuary service atonement was made for the sinner, not by the slaying of the sacrificial offering, but by the priestly ministry performed within the sanctuary after the sacrifice had been slain: "And he [the penitent] shall lay his hand upon the head of the sin offering, and slay the sin offering in the place of the burnt offering.
"And the priest shall take of the blood thereof. . . . And the priest shall burn it [the fat] upon the altar for a sweet savour unto the Lord; and the priest shall make an atonement for him, and it shall be forgiven him" (Lev. 4:29-31; cf. v. 27).
They contended that the atoning ministry of Christ in the heavenly sanctuary since His ascension—and not His sacrifice on Calvary—was the biblical counterpart of the atoning ministry of the priest in the earthly sanctuary after the sacrifice had been slain (Heb. 9:11-15, 23-26; 10:11-14; cf. Lev. 4:27-31, etc.). Thus when Miller and other early Adventists spoke of the atonement as being made not on the cross, but by Christ after His ascension to heaven, they were technically correct insofar as the use of the word "atonement" in ritual law was concerned. However, contemporary theological usage of the word "atonement" does not include its biblical application to the priestly ministration of the blood of a sacrifice that had already been slain. This is the reason the Seventh-day Adventist position on the atonement has sometimes been misunderstood and misrepresented. In any discussion of the atonement, it is important that this distinction between biblical and modern theological use of the word be recognised.
The relationship between Christ's sacrifice on the cross and His priestly ministry in heaven since His ascension is explained thus by Ellen G. White: "The intercession of Christ in man's behalf in the sanctuary above is as essential to the plan of salvation as was His death upon the cross. By His death He began that work which after His resurrection He ascended to complete in heaven" (GC 489).
"The great sacrifice had been offered, and had been accepted, and the Holy Spirit which descended on the day of Pentecost carried the minds of the disciples from the earthly sanctuary to the heavenly, where Jesus had entered by His own blood, to shed upon His disciples the benefits of His atonement" (EW 260; first published in 1858 in 1SG 170).
But that this position in no sense depreciates the atonement provided at the cross is evident from her further comments: "The sacrifice of Christ as an atonement for sin is the great truth around which all other truths cluster" (Ellen G. White, in SDACom 5:1137).
"The cross must occupy the central place because it is the means of man's atonement and because of the influence it exerts on every part of the divine government" (6T 236).
"Christ's words on the mountainside [in Galilee after the Resurrection] were the announcement that His sacrifice in behalf of man was full and complete. The conditions of the atonement had been fulfilled; the work for which He came to this world had been accomplished" (MS 138, 1897).
When SDAs speak of Christ's work of atonement in the heavenly sanctuary, they refer to the application to each individual believer, according to his/her need, of the benefits of salvation provided for all at Calvary.
In the ancient sanctuary the solemn services of the annual Day of Atonement brought the yearly ritual cycle to a close (Lev. 16). The work of atonement, or reconciliation, performed on that day brought to completion all that the sanctuary and the priests could do for repentant sinners, and cleansed the sanctuary and the people. On the basis of the clear analogy drawn by the inspired writer of Hebrews between the earthly sanctuary and that in heaven, SDAs recognise in the final phase of the heavenly ministry of Christ a counterpart of the earthly Day of Atonement service. SDAs refer to this concluding phase of Christ's ministry of reconciliation as the "great antitypical day of atonement," and the "investigative judgement" (see also Sanctuary).
The need for a reconciliation, or atonement, between God and humanity derives from the fact that when Adam sinned "sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned" (Rom. 5:12; cf. 3:23). Disobedience separated human beings from their Maker, and the outraged divine law demanded the death of the transgressors. God's justice required that all imperfection must be eradicated. But since humans were the offspring of a loving Creator, almighty love planned a way of escape for those who had fallen into the trap of sin set for them by Satan.
Being a reflection of the character of God, the moral law is immutable. There is nothing sinners can do to recommend themselves to God or to bring about reconciliation. Accordingly God made provision for reconciling sinners to Himself should the need arise. The plan was devised before the creation of Adam (1 Peter 1:20), and explained to him before his expulsion from Eden (Gen. 3:15). This plan called for the Son of God to lay aside His divine power, to be clothed with a human body, to meet temptation as humans must meet it, yet without sin, and to die a vicarious death in the sinner's place. He would be treated as the worst of sinners, and experiencing separation from the love and presence of the Father, He would suffer for all sinners. He paid the price of sin and offered humanity His righteousness.
John 3:16 summarises the plan of the atonement: "For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life." The love of God is free, but it must be believed and accepted voluntarily. It is available to all, but not all accept it. There can be no atonement for those who "neglect so great salvation" and refuse to "live by faith" (Heb. 2:3; Rom. 1:17). A complete atonement must not only afford pardon for past sins but also provide human beings with power to overcome temptation. For this reason Christ lived among humans as their example and also offers them the Holy Spirit to enable them to live sinless lives -- Seventh-day Adventist Encyclopaedia.