Andrew Walls (1928–2021) has been called the “most important person you don’t know.”¹ He was a Scottish scholar with an Oxford pedigree who devoted much of his life to serving the African church and challenging the academic community to turn its attention to the remarkable growth of Christianity in the non-Western world.

The numbers are staggering. In the year 1900, some 82 percent of the world’s Christians lived in Europe and North America. By 1970, the number of Christians in the Global South had grown to more than 40 percent, reaching nearly 70 percent in 2020!² Walls could feel the changes taking place around him while he was teaching church history in Nigeria in the 1950s and 1960s, and he remained active in teaching World Christianity right up until his death at the age of 93.³

How could historians make sense of the explosive growth of Christianity in the Global South?

Missions Is Not the Bomb

One of the many trends Walls noticed was that the church was growing in the main through indigenous witness and local revivals. This was instructive for teaching church history and understanding Christian missions. He insisted that scholars needed to place a greater focus on the African, Asian, and Latin American church in situ rather than simply relegating their entire story to a summary chapter on the history of missions.⁴ He pleaded with scholars to start teaching “church history” and stop teaching “clan history.”⁵

At the same time, Walls stressed that “it is difficult to imagine that the change [the rapid growth of Christianity in the Global South] could have occurred without the missionary movement.”⁶ And then he captured the importance of Christian missions in one sentence: “Missions were not the bomb, but they were the detonator, and as a result Africa and Asia and Latin America have become important theaters of Christian activity, the representative Christianity of the twenty-first century.”⁷ Missions had triggered the explosive growth of Christianity in the Global South.

Indispensable Detonator

Christian missions as the “detonator” for the explosive growth of Christianity is an insightful metaphor. On the one hand, it tames our pride, reminding missionaries (especially those from the West) that they are part, not the whole, of the work that God is doing in the global church. The Lord of the harvest has poured out his Spirit on all flesh and is using people all over the world to spread the gospel. The work of Western missionaries is only part of the story.

On the other hand, the “detonator” imagery infuses the entire church with a sense of urgency: someone must ignite the Spirit-primed explosion that will set the world aflame with the love of God. As John Piper has taught us, we aim in missions “to bring the nations into the white-hot enjoyment of God’s glory.”⁸ Missions is essential for this task.

God has been working in powerful ways through the missionary efforts of his people for two thousand years. When the Spirit of God came blowing in, setting tongues on fire in Jerusalem in the early first century, he translated the message into the languages of the earth. The miracle at Pentecost made clear that the good news was for all people “from every nation under heaven” (Acts 2:5). The Acts narrative shows that “word of God increased and multiplied” through missionaries and martyrs who could not remain quiet about the things they had “seen and heard” (Acts 4:20).

In the world of late antiquity, the Christian faith spread along Roman roads to the West, and silk routes to the East. To borrow from the mission historian Stephen Neill, these early witnesses to the gospel were possessed with a “burning conviction” that “a great event had burst upon them in creative power.”⁹ During the medieval period, contrary to popular imagination, the flame continued to spread through missionaries who followed Paul’s counsel to remain single so that they could offer their lives “with undivided devotion to the Lord” (1 Corinthians 7:35). Missionary monks gave up homes and families to carry the gospel to the “ends of the earth.” ¹⁰ During the Age of Discovery, following the European Reformations, Catholic and Protestant missionaries boarded ships, leaving kith and kin, bound for Africa, Asia, and the New World, inflamed by the love of Christ for the salvation of the world.

The evangelical revivals of the eighteenth and nineteenth centuries created an unprecedented wave of missionary fervor, and helped usher in the new era of world Christianity in our own day.

Igniting Transformation in the Dark

By the year 1900, there were some 62,000 cross-cultural missionaries, increasing to 240,000 by 1970, and some 420,000 by century’s end! ¹¹ Most were young, more than half were women, and many left prestigious schools like the University of Cambridge to lay down their lives for the gospel.¹²

“Missions is the means God has chosen for igniting transformation in the dark corners of the world.”

Academic presses are now churning out research showing direct causation between missionary fervor and the new era of world Christianity. As it turns out, Barbara Kingsolver’s missionary caricature of a failed Southern Baptist missionary in the Congo is misleading. To quote Philip Jenkins, “The runaway success of Christian missions to Africa and Asia are all the more striking in view of the extraordinarily poor image that such activities possess in Western popular thought.”¹³ Missionaries set off an explosion that has changed the course of human history.¹⁴

The rapid growth of Christianity is cause for celebration, but not complacency. About 40 percent of the world’s population, or approximately 3.5 billion souls, remain culturally cut off from the gospel. The vast majority of these unreached people groups do not know a Christian, do not have access to the Scriptures in their own language, and do not live in proximity to a local church. Missions is the means God has chosen for igniting transformation in the dark corners of the world.¹⁵

Can Local Pastors Change the World?

I know from personal experience that one of the great perils of pastoral life is that we become so preoccupied with important matters in our local churches that we can fail to see the urgent needs in the world. It is instructive that the word parochialism, meaning “narrow-minded,” is derived from the Anglo-French word parish. Pastors can become so involved in their local parish that they become parochial parsons. It is easy to do. It can happen to any of us. If you are a pastor or a Christian leader, bringing change to the world may need to begin with you.

“We become so preoccupied our local churches that we can fail to see the urgent needs in the world.”

How might pastors help fan the flame of missions today? Take up and read in order to learn about the work God is doing in the world and the work that remains unfinished. These developments are not happening in a corner. Go and see the church at work in the world — and go to learn. Like Peter in Acts 10, eat and drink with your brothers and sisters and let God change you by your encounter with people in other lands. Encourage people you know to go on short-term trips, and use the help of experienced guides. Don’t just send your people to go paint the orphanage.¹⁶ Challenge your people to give to ignite change through giving to worthy causes, such as sending a missionary, translating the gospel into a local language, planting an indigenous church, or equipping underserved pastors, evangelists, and missionaries who have ready access to unreached people groups. Finally, send missionaries out, laying hands on no person quickly (1 Timothy 5:22). Combine zeal with knowledge (Proverbs 19:2).

Don’t waste your influence. Don’t let your people waste their lives. Fan the flame that is in you, and help start a blazing fire somewhere in the world.