Revelation 14:6,7 - And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people, Saying with a loud voice, Fear God, and give glory to Him; for the hour of His judgment is come: and worship Him that made heaven, and earth, and the sea, and the fountains of waters.
2SM 106 - “The message proclaimed by the angel flying in the midst of heaven is the everlasting gospel, the same gospel that was declared in Eden.”
GC 356, 380 - “A great religious awakening under the proclamation of Christ's soon coming is foretold in the prophecy of the first angel's message of Revelation 14... The first angel's message of Revelation 14, announcing the hour of God's judgment and calling upon men to fear and worship Him, was designed to separate the professed people of God from the corrupting influences of the world and to arouse them to see their true condition of worldliness and backsliding.”
FLB 212 - “As the books of record are opened in the judgment, the lives of all who have believed on Jesus come in review before God. Beginning with those who first lived upon the earth, our Advocate presents the cases of each successive generation, and closes with the living. Every name is mentioned, every case closely investigated. Names are accepted, names rejected. When any have sins remaining upon the books of record, unrepented of and unforgiven, their names will be blotted out of the book of life, and the record of their good deeds will be erased from the book of God’s remembrance... All who have truly repented of sin, and by faith claimed the blood of Christ as their atoning sacrifice, have had pardon entered against their names in the books of heaven; as they have become partakers of the righteousness of Christ, and their characters are found to be in harmony with the law of God, their sins will be blotted out, and they themselves will be accounted worthy of eternal life..."
1888 939, 940 - “The work for this time is represented by the first, second, and third angels flying in the midst of heaven. The first angel has his message, the second follows the first and bears his message. But the first is not dropped; it loses none of its force as the second is proclaimed. So also with the third. These angels represent the people of God proclaiming the word of God to the world, whereby are produced impressions so powerful that truth is separated from the rubbish of error and stands revealed in its unblemished pure beauty. These messages of truth open the most lofty contemplation of scenes through which they conduct us-- solemn, refining, and awfully grand.”