The term, “Great Commission,” and its associated theology and philosophy of ministry is derived from Matthew 28:18-20, which reads:
"And Jesus came and said to them, 'All authority in heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.'”
A complimentary verse to the above “Great Commission” passage is Acts 1:8, which reads:
"But you will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem and in all Judea and Samaria, and to the end of the earth."
The Great Commission is God’s Plan for Building His Church
The “Great Commission” is God’s three-fold plan for building His Church, the Body of Christ. His plan involves the making of disciples, the confirmation and affirmation of disciples, and the ongoing teaching of disciples.
A person cannot be a true disciple of Jesus Christ until he or she is born-again--until he has come to genuine repentance and faith in the Lord Jesus Christ. So, the first step in fulfilling the “Great Commission” is evangelism. A person must be made a disciple before he can be a disciple. Christians are commanded by God to go everywhere, from their living room to the farthest reaches of the Earth, to take the gospel to an unsaved world.
Once a person becomes a follower of Jesus Christ--a learner, a student, a disciple--he must testify publicly through the ordinance of baptism. Baptism has a two-fold purpose. For the disciple, it is the outward proclamation of the inward change of the heart and soul accomplished by Jesus Christ. Baptism also serves as a means for the local assembly of believers (the church) to confirm the disciple as a follower of Christ, and to affirm the disciple’s entrance into the Christian family.
Once a person is born-again, becomes a disciple, and is affirmed and welcomed into the Body of Christ through the ordinance of baptism, it is the ongoing responsibility (until the Lord returns) of fellow believers to “[teach] them to observe all that [Jesus has] commanded.” The “Great Commission” does not end with evangelism. That is only the beginning. The “Great Commission” includes the responsibility of every Christian to help their fellow Christians to grow in their faith in Christ and their understanding of His Word.