Effective missionaries, having learned language and culture and shared their faith, begin the Growth Period with a vision of how God will use them to mobilize a movement in the area where they are working. They realize that their task is not merely to plant a church but to initiate a movement of God. They have developed the cultural and linguistic understandings to think missiologically about their cultural context.
Developing a strong movement of God in a new city or ethnic area requires the accomplishment of three essential interrelated tasks during the Growth Period. First, initial evangelism leads to the planting of new churches. Second, Christians are nurtured to maturity within these churches. Third, leaders are trained to evangelize and plant other churches, pastor and shepherd the community of believers, and train still other leaders. Effective missionaries successfully develop models for accomplishing each of these central missionary tasks. While other missions endeavors may amplify these three central tasks, without them a strong movement of God cannot come into being. In receptive areas of the world the accomplishment of these three tasks will require a minimum of eight to ten years of focused ministry during the Growth Period to enable mature local churches with trained leadership to come into existence.
Care must be taken that these three tasks not be performed artificially by inducing people to come to Christ because of finance or favor. Western missionaries come from very wealthy countries. Without realizing it, they frequently magnetize the leeches and con men of the culture and then attempt to build a church around them. Effective learning during the first stage equips effective missionaries to deal with the many dilemmas concerning the disparity of wealth in the world and the resulting expectation of the poor. God’s church, moreover, must reflect the compassion of God for the poor and disenfranchised. God’s people are called to preach good news to the poor, freedom for prisoners, recovery of sight for the blind, and release for the oppressed (Luke 4:18-19). These ministries, however, occur within the context of genuine Christian conversion: Unbelievers must "open their eyes and turn them from darkness to light, and from the power of Satan to God, so that they may receive forgiveness of sins" (Acts 26:18).
Perhaps the greatest challenge during this stage is developing an effective paradigm of church planting which is both biblically integrated yet reproductive. For example, one missionary team may plant a single church in a city or ethnic unit while another employs a multi-church orientation to plant numerous viable churches within the same culture. One team may smother national leaders by micro-managing church affairs; another may work with maturing leaders to develop models of mobilizing national leadership. The difference between these two works is the models or paradigms used in church planting and development.
Church planting teams in receptive areas should develop a full-city, multi-city, or full-tribe perspective rather than expecting to plant only one local church. Their model should be that of Paul, who planted and nurtured but expected Apollos to water (Rom. 15:17-20; 1 Cor. 3:6, 10). When a team focuses on establishing one church, a missionary enclave is almost always created, and the presence of many trained foreign leaders tends to smother development of national church leaders. Frequently only an anemic church, transplanted from the sending culture, is established. This church can only learn to grow and develop naturally when it learns to live within the social and economic realities of its own culture after the missionaries leave.
The nature of identification during the Growth Period becomes more focused: Missionaries identify with (1) the broken sinfulness of unbelievers in order to lead them to Christ, (2) the struggles of new Christians to nurture them to grow to maturity, and (3) the equipping needs of developing leaders to empower them in ministry. In this stage the missionary is more than just a learner; he is an evangelist and church planter, a nurturer of new Christians, and a trainer of developing leaders.
Our team working among the Kipsigis of Kenya developed a new paradigm of church maturation during the Growth Period appropriate for the context in which we were working. We sought to mature churches through four distinct stages. The first converts were brought to Christ through evangelism during the Initial Church Stage, a time lasting from five to ten weeks. During this stage, church planters served primarily as evangelists who proclaimed the foundational message of the gospel. The objective of this stage was to gain enough converts to form a vibrant group; the joy was seeing a congregation born through public and private proclamation of the gospel.
The second stage of church maturation, called the Developing Church Stage, sought to form a sustaining fellowship from those converted during the initial stage. Initial Christians were nurtured to become germinally reproducing, cohesive bodies through teaching and modeling of evangelism and church life. Church planters served throughout this stage as church maturers, nurturing members of the body to serve the function that God had given them within the body. As mentors of new Christians, the missionaries spent one or two days each week visiting from house to house and holding evangelistic and nurturing meetings throughout the village. The objective of this stage was to mold initial Christians into a body; the joy was seeing new Christians grow into a cohesive body able to stand on their own. This stage took from six to fifteen months, depending on how quickly the churched matured as a body. Interestingly churches who rapidly became spiritually and numerically strong tended to become the most mature of the churches in their respective areas.
The third period of church maturation, the Independent Church Stage, began when founding church planters were able to allow local leaders to assume all major leadership roles. Frequently a rite of separation--a time of commissioning, of laying on of hands to commend the new church to the Lord--signaled entry into this stage. The church had developed enough leadership to function as a cohesive body without the continual presence of the initial church planting missionary.
While the focus during the Developing Church Stage was on congregational training, the emphasis during the Independent Church Stage was on leadership training. During the previous stage, leaders rose naturally to the surface as all members were taught the basics of the Gospel and nurtured to become participants in cohesive fellowships. In this stage special training was given to leaders to develop theological understandings and skills for practical ministry.
Thus effective church planters among independent churches grew to becatalysts training congregational leaders. The objective was to train leaders to the point that local Christians were able to "build themselves up in love" (Eph. 4:16); the joy was seeing congregational leaders develop.
The Mature Church Stage was the final period of church maturation. At the beginning of this stage and after intense leadership training during the Independent Church Stage, church leaders were selected and ordained. Elders were selected to pastor the flock; deacons were selected to serve in various ministries; evangelists were set aside to lead the congregation in proclaiming God's redemptive message both in the local village and in adjoining areas; Sunday school teachers and other ministry leaders were also selected. As the founding church planters looked at the church, they saw with joy how God had worked to bring this body to maturity. Because trained leaders had been ordained, founding church planters assumed the role of occasional guests, who came periodically to exhort and strengthen the body. They were, however, no longer needed for its ongoing. Church planters, resisting the temptation to maintain control over the mature church, had to allow the church to continue on its own.
Many missionaries consider their task complete when a number of churches have been planted and leaders trained to minister within their local congregations. But communities of faith frequently erode if they are left as autonomous bodies without continued nurturing. The work of church planting and development is not completed when local churches come into existence. These local churches need nurturing, equipping structures which tie them together as a movement and which empower ministers and elders as spiritual leaders to pastor their congregations and continue the process of local evangelism and church planting. This need for structures of continuity leads to the third period of church development.
 Thinking missiologically implies that missionaries are able to communicate God’s eternal message in cultural metaphors and forms that both make the message intelligible and stir the hearts of people to accept its presuppositions. It also infers the skill of developing unique strategies of church planting and development that are appropriate to the cultural context.
 For further perspectives on the three essential tasks of missions readMissions: Biblical Foundations and Contemporary Strategy (1996, 147-175) or "The Essential Tasks of Missiology".
 Jonathan’s Bonk’s Mi$ion$ and Money (Orbis, 1994) is a significant book describing the dilemmas about those seeking finance and favor when hearing the Christian message from westerners. Robertson McQuilkin’s article "Stop Spending Money" (Christianity Today 1999) will also become a classic description of wrong use of money.
 These missionary roles coincide with the three major tasks of missionaries during this stage.
 These four stages are discussed more fully in Missions: Biblical Foundations and Contemporary Strategies (1996; 156-159) or "The Essential Tasks of Missiology"