The "everlasting gospel" is the same in all generations; but the revelation of the light of truth regarding Christ's righteousness is continually unfolding, clearer and brighter, with the end result of making a people ready for the coming of the Lord (Prov. 4:18). "We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts" (1 Peter 1:19).
There is a distinct difference between the 1888 message and that of the Protestant Reformers. Ellen White's clear statements are to the effect that the 1888 message is the beginning of the "latter rain" and the "loud cry" (Testimonies to Ministers and Gospel Workers, p. 92; Review and Herald, Nov. 22, 1892).  The Reformers taught much truth; but never did they proclaim the full light of glorious truth prophesied in Rev. 18:1. To say that the three angels' messages were proclaimed by the Reformers is to deny what God has taught us in our history (Life Sketches, p. 196). 
This message was particularly a presentation "of the righteousness of Christ in relation to the law ... not presented ... in this light heretofore" by our people (The Ellen G. White 1888 Materials, p. 164). The Reformers never really understood the law in its magnitude (Isa. 42:21). Ellen White made this statement at Minneapolis: "Said my guide, 'There is much light yet to shine forth from the law of God and the gospel of righteousness. This message, understood in its true character, and proclaimed in the Spirit will lighten the earth with its glory.'" (1888 Materials, p. 166). A. T. Jones and E. J. Waggoner began to present the law in a way that truly "magnified" it and made it "honorable" as we have never read it in Luther and Wesley and other Seventh-day Adventist writers. She highly recommended Jones' and Waggoner's presentations as light sent of God. Had their message not been resisted and rejected, their simple, heart-warming presentations would have broken down the prejudice of many in the popular churches. "The Lord designed that the messages of warning and instruction given through the Spirit to His people should go everywhere. But the influence that grew out of the resistance of light and truth at Minneapolis, tended to make of no effect the light God had given to His people through the Testimonies" (Feb. 28, 1893, 1893 General Conference Daily Bulletin, p. 407).
The message of 1888 was an understanding of righteousness by faith that was in harmony with the cleansing of the sanctuary. The Reformers had no concept of that doctrine. Adventist's concept of righteousness by faith is not the same as the Reformers. The ethical significance of the cleansing of the sanctuary will certainly be to prepare a people for the coming of the Lord, "not having spot, or wrinkle, or any such thing," (Eph. 5:27) a community of God's people which will "come ... unto a perfect man, unto the measure of the stature of the fullness of Christ" (Eph. 4:13).
Their message, as God intended it, would have brought deliverance from the root of sin, the love of self. It follows that genuine and complete acceptance would have made a people ready for the coming of the Lord in that very generation. It is no disparagement of saints who are at rest to say that God intends His people to progress continually toward actually reaching a higher standard than any previous generation reached, nothing less than perfect likeness to Jesus in character. This experience is quite distinct from the "justification by faith" preached by the Reformers. Ellen White frequently describes the 1888 message as "the message of Christ's righteousness" more than as "justification by faith," though she did occasionally use the latter term. Luther is wonderful, and he pioneered the way; but Jones and Waggoner went much further.
They had a clearer concept of the love of God in Christ than did the Reformers. They understood that righteousness by faith is based on genuine love, and began to break up the synthesis of Hellenistic self-centered love and New Testament agape (which is self-giving love) that had weakened Seventh-day Adventists prior to 1888. They restored New Testament love to its rightful place as the constraining power that makes a new life.
--Paul E. Penno
 "This is the message that God commanded to be given to the world. It is the third angel's message, which is to be proclaimed with a loud voice, and attended with the outpouring of His Spirit in a large measure" (Testimonies to Ministers and Gospel Workers, p. 92).
 "We have nothing to fear for the future, except as we shall forget the way the Lord has led us, and His teaching in our past history" (Life Sketches, p. 196).