The messages are an end-time proclamation

Judgment-hour message only for the last days—The message itself sheds light as to the time when this movement is to take place. It is declared to be a part of the “everlasting gospel;” and it announces the opening of the judgment. The message of salvation has been preached in all ages; but this message is a part of the gospel which could be proclaimed only in the last days, for only then would it be true that the hour of judgment had come. The prophecies present a succession of events leading down to the opening of the judgment. This is especially true of the book of Daniel. But that part of his prophecy which related to the last days, Daniel was bidden to close up and seal “to the time of the end.” Not till we reach this time could a message concerning the judgment be proclaimed, based on the fulfillment of these prophecies....3AM 38.4

No such message has ever been given in past ages. Paul, as we have seen, did not preach it; he pointed his brethren into the then far-distant future for the coming of the Lord. The Reformers did not proclaim it. Martin Luther placed the judgment about three hundred years in the future from his day. But since 1798 the book of Daniel has been unsealed, knowledge of the prophecies has increased, and many have proclaimed the solemn message of the judgment near.—The Great Controversy, 355, 356 (1888, 1911)3AM 39.1

To prepare God’s people—To prepare a people to stand in the day of God, a great work of reform was to be accomplished. God saw that many of His professed people were not building for eternity, and in His mercy He was about to send a message of warning to arouse them from their stupor and lead them to make ready for the coming of the Lord.3AM 39.2

This warning is brought to view in Revelation 14. Here is a threefold message represented as proclaimed by heavenly beings and immediately followed by the coming of the Son of man to reap “the harvest of the earth.”—The Great Controversy, 311 (1888, 1911)3AM 39.3