Most every Christian believes that there will be a "last" generation—that is, a "final" generation. It seems so obvious! The issue seems to be its significance. Many believe that God is delaying the Advent, waiting for something special to develop in the "last" generation and have expressed this concept as "the harvest principle."
The harvest principle is derived from several biblical concepts concerning the Advent that otherwise remain disconnected and isolated. The essence of this principle has been reflected in adventist thinking for more than a century from such early leaders as the Whites, Loughborough, Bordeau, Smith, Haskell, Prescott—and many more since.
Distancing from many Christians who also emphasize the return of Jesus (for example, those of the secret rapture notion) the harvest principle emphasizes the conditionality of the Advent—that God will wait for a ripened harvest (Mark 4:29, Revelation 14:15, 16)—a prepared people who will vindicate His integrity and law—and that such a people become His faithful instruments of grace as He appeals personally through the Holy Spirit and through His people to the last generation worldwide to accept His invitation to live forever.
Adventists believe that evil will abound and worsen as the numbers and ingenuity of the human race increase, but the world will not destroy itself. Nor will the increase of evil, of itself, hasten or determine our Lord's return. On the contrary, heavenly forces "hold" the winds of terror until God's people are finally identify as those who can be stamped with God's seal of approval (Revelation 7:1-3). On Planet Earth, the great controversy will be played out. Before probation closes and evil is unrestrained, men and women will settle forever any question regarding the fairness and love of God.
Some believe that Christ's return depends upon the sovereignty of God—that Jesus will return at a particular time God has set, independent of human behavior. This Calvinist thinking, contrary to John Wesley's (for example) is overruled by the larger, more expansive understanding of the "everlasting gospel," which is best expressed in the coherent, synoptic understanding of the issues in the Great Controversy Theme.
Biblical texts such as 2 Peter 3:11, 12 and many Ellen White comments such as Christ's Object Lessons, page 69, teach that spiritual maturity of God's people has much to do with the timing of the Second Advent. I find no biblical or White statement that contradicts the harvest principle.
After Jesus described the kind of world conditions that would exist from His day to the end, He said, "See that you be not troubled: for all these things must come to pass, but the end is not yet. ... All these are the beginning of sorrows" (Matthew 24:6-8). In verse 14, Jesus gives us a positive sign that determines the nearness of the Advent: "And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come."
What that gospel is and how it is preached is the key to last-day events. To place undue emphasis on world conditions, always in turmoil, as the chief signs of the end of the world, would be similar to a farmer saying, "I oiled my combine; it must be time to harvest the wheat." Or, "It looks like there will be a thunderstorm, it must be time to pick my corn." There is as much relationship between a thunderstorm and picking ripe corn as between distress in the world and readiness of men and women for the Advent.
The harvest principle seems to be the best explanation to unite comments regarding 1) God's eagerness to punish men and women who have "Filled up their cup of iniquity" with 2) His eagerness to "thrust in [His] sickle and reap, for the harvest of the world is ripe" (Revelation 14:15, 18). God will indeed lift His restraining hand off Satan after He has "sealed the servants of God in their foreheads (Revelation 7:3). God will not close this world's probation until all living at a given time have had a fair opportunity to see and hear the difference between those who truly keep His commandments and those who finally say No to His appeals—they will get their way, and God will leave them alone! Being left alone, after filling up their cup of iniquity," with Satan's evil hand unrestrained, is to suffer the "wrath of God."
In other words, the harvest principle highlights the ripening of wheat and tares—the saved and the lost. The increasing clarity of God's loyalists in witnessing to the "everlasting gospel" and to their unambiguous public witness to this gospel will hasten previously curious or hesitant people into a mind-set of either acceptance or rejection of these life principles that ultimately leaves no room for neutrality.
The harvest principle demolishes, on one hand, the thought that 1) time will continue endlessly, and, on the other, 2) that God will come, ready or not! God will not change His strategy regarding how He prepares people to be entrusted with eternal life—even though it seems that He has the right to exhaust His patience with wicked men and women who seem to be increasingly violent and self-serving.
Ellen White was instructed to say: "The great, grand work of bringing out a people who will have Christlike characters, and who will be able to stand in the day of the Lord, is to be accomplished."—Testimonies, vol. 6, p. 129. Some generation of Adventists, and many more throughout this planet, will take God seriously, listen to His Work very carefully, and respond with a resounding Yes to whatever God makes clear in the toughest of time.