The Millerites had firmly believed that Jesus Christ would return to earth on October 22, 1844. When the Second Coming did not take place, many Millerites were not just disappointed: they were disillusioned, and gave up belief in a literal second advent. Others, however, went back to studying the scriptures with renewed determination.

Over the next 19 years, former Millerites identified a series of Bible truths forgotten since the days of the early Church. Yet there was still no Seventh-day Adventist Church—only small groups scattered across the northern United States, who did not yet even have a name for themselves, though some, like James White, identified themselves as belonging to “the Great Second Advent Movement.”

Gradually, however, inspired by Christ's great commission to “Go and make disciples,” the seventh-day sabbatarian adventists recognized the need to organize, so they could more effectively and more widely proclaim the third angel’s message. Eventually, in 1863, the “General Conference of Seventh-day Adventists” was founded—an organized church, focused on mission and on proclaiming the good news of a God who created us, lived among us, died for us, and redeems us.

Because our image of the founders of our church is shaped by photographs of middle-aged men, we often do not realize how diverse they were.

They were young. At the time of the Great Disappointment of 1844, James White was 23; Ellen White and Annie Smith were 16; John Andrews 15; Minerva Loughborough was 14, while John, her brother, and Uriah Smith were only 13; and George Butler was just 10. Yet it was these young men and women, aided by elder statesmen like Joseph Bates (aged 52 in 1844), who led in the key steps that resulted in establishing the General Conference in 1863.

Among the first members of the newly created church, women were prominent. In addition to Ellen White, there were Minerva Chapman (née Loughborough), a key figure in the early publishing work and later treasurer of the General Conference; Maud Sisley Boyd, later a pioneer missionary to Europe, South Africa, and Australia; and Nellie Druillard (née Rankin), later a pioneer missionary to Africa and an influential educator and health reformer. Also among those first members of the Seventh-day Adventist Church was the Hardy Family, of African-Americans.

As we mark 150 years of Seventh-day Adventists being united for mission, there is more need than ever for Adventist men and women of all ages, young and old as well as middle-aged, and of all ethnic and social backgrounds, to follow the example of our founders. Founded in love for our Savior and His love for sinners, we need to proclaim Christ and Him crucified, and His desire that we “keep the commandments of God and the faith of Jesus” (Rev. 14:12).

Our 150th anniversary is not a time for celebration—those who founded the GC in 1863 would not have expected Adventists to still be on earth in 2013! The worldwide church has designated Sabbath May 18, 2013, as a day of prayer, remembrance, and recommitment to mission. Each local congregation is encouraged to find appropriate ways to mark the “sesquicentennial” of the Seventh-day Adventist Church, including a focus on their local church history. Church elders have a vital role to play in the call to remembrance and recommitment.

Now is the time for individual Adventists and congregations to remember how God has led His remnant church “and His teaching in our past history” (Life Sketches, p. 196). Now is the time to reflect on what we have done, and not done, that grieves our God— and to repent. Now is the time to commit ourselves, both individually and corporately, not just to “a revival but [to] a reformation,” as Ellen White urged (R&H, July 15, 1902, p. 7). Now is the time to pledge ourselves anew to preaching “the everlasting gospel … to every nation, tribe, tongue and people” (Rev. 14:6).

As we reflect on 150 years of the Seventh-day Adventist Church being united for mission, now is the time for us to honor the memory of our pioneers and to honor our God by recommitting ourselves, regardless of age, gender, color or race, to the prophetic destiny of the Great Second Advent Movement.

David Trim is the director of Archives, Statistics, and Research at the General Conference of Seventhday Adventists.