Being an evangelist is more than just telling people about Jesus; it requires that we become teachers of the gospel. The gospel is proclaimed by the preaching of the good news. This is the beginning. But we also need to explain to new believers the implications and consequences of believing in the gospel. This is necessary to make real disciples.
The Authority to Teach
R.T. France notes that when Jesus said to His disciples that they would have to teach, He was transferring to them the authority to be teachers. In 28:20, Matthew uses for the first time the verb "teach"—didaskō—which implies that the disciples then had authority from Christ to teach others.
Believing in the gospel requires the newborn believer to submit to teaching and to receive instruction in order to live according to Jesus' will. Making disciples starts with the confession of faith in Christ (Rom. 10:9); then, baptism in the name of the Father, Son, and Holy Spirit so that we can join the church in order to learn to observe all that Jesus has commanded us in the context of a community of believers.
The Need to Teach
The fact that the church has been established by Jesus to be a teaching community is clear. And if this is the nature of the church, then Christian ministry is mainly a teaching ministry.
In Acts 2:42, we learn that the primitive church gathered together to devote themselves to the Apostles' teaching and to fellowship, to the breaking of bread and to prayer. The first Christians prioritized their time together in order to comprehend the gospel and its implications in their lives. The Apostles formulated the gospel. Then the preachers proclaimed the gospel and the teachers taught the ethical implications of the message.
God has given the church gifts in order to keep the gospel at the center of the new community. Paul, in his second letter to Timothy, says, "For this gospel I was appointed a preacher and apostle and teacher" (1:11). All the gifts and status given to Paul were used to serve the gospel. The church, then, should be the guardian of the gospel, and everything the church does and every ministry in the church should be an instrument for the promotion of the gospel and the advance of Christ's kingdom. This is the only way to fulfill the Great Commission.
What to Teach
As we evaluate which teachings are essential for new disciples, we may want to consider what Derek Tidball suggests were Paul's teaching goals:
He (the apostle) wants his disciples to grow up, to become mature adults, no longer infants and children (1 Cor. 3:1–4; 14:20; Eph. 4:14–15). He wants the bride to be a virgin, betrothed to one husband, with eyes for no one else (2 Cor. 11:2). Using imagery from the gymnasium and the athletics track, he wants them to develop strength, build stamina and not be feeble in faith (1 Cor. 9:24–27; Eph 4:16; 1 Thess. 3:2; 2 Thess. 2:17, 3:3). Using agricultural imagery, he wants the roots to go down deep and see fruit development (1 Cor. 3:5-9; 2 Cor. 9:10; Gal. 5:22 Phil. 1:11; Col. 1:10; 2:7). Using educational imagery, he wants them to "learn Christ" (Eph. 4:20).
Tidball demonstrates here the rich diversity of teachings that disciples are to receive but which are nonetheless focused on one goal: the creation of strong, mature believers.
When Paul knew that he was close to death, he reminded Timothy of his duty to the gospel. The heart of his ministry was to preach and teach the gospel, to defend it against attack and falsification, and to ensure its accurate transmission to the generations to come. Timothy was charged to guard the gospel (2 Tim. 1:14), to suffer for the gospel (2:3, 8–9), to continue in the gospel (3:13–14), and to proclaim the gospel (4:1–2). This is the greatest privilege and duty that can be entrusted to a teacher: to be the guard of the gospel and to teach it faithfully to faithful disciples.