The church needs theology to make disciples, both those who are brought into the church and those who are built up in the truth.
Theology, the truth that is from God and about God, is for the life of the church. Jesus is building His church by making disciples who follow Him, confessing the truth that He is “the Christ, the Son of the living God” (Matt. 16:16). Disciples are those to whom Jesus gives life so that they will walk in His way according to His truth. As Jesus said, “If you abide in my word, you are truly my disciples, and you will know the truth, and the truth will set you free” (John 8:31–32).
In the Great Commission, Jesus sends His disciples to make disciples and build His church throughout the world. How are the disciples to make disciples? Jesus sums up that huge task in two remarkably brief points: His disciples will make disciples by baptizing them and by teaching them. If these words of Jesus were not so familiar, many of us might find this summary somewhat surprising. We might well expect the commission to teach, but including the commission to baptize in such a short summary is perhaps unexpected. But surprises invite reflection and meditation. As we think about it, we can see how appropriate and helpful this is.
We see in this commission that the making of disciples has two parts: bringing them in and building them up. Disciples are those who have been brought in by baptism and are built up by teaching that changes lives.
Jesus directs our attention to baptism not in the narrow sense of just the water ceremony but in the broader sense of all that baptism involves. We can see this clearly in the ministry of John the Baptist. His ministry of baptism includes his preaching of good news (Luke 3:18), his call to repentance (v. 3), and his insistence on the fruit of repentance (v. 8). Baptism includes both preaching the promises of God and calling for the proper response to those promises. Baptism truly brings disciples in, calling them to begin the life of faith.
Baptism in this sense is properly foundational to being a disciple because baptism holds forth the promises of God and also calls for the faith and commitment of those baptized. The central promise of God to sinners in baptism is that God will wash away their sins and forgive them. When Jesus in the Great Commission specifies that His disciples will baptize in the name of the Father, the Son, and the Holy Spirit, He shows that the promise of baptism comes from the triune God and is guaranteed by the Trinity.
The baptismal liturgy of the Dutch Reformed churches, written in the sixteenth century and used for centuries in those churches, helpfully elaborates on the distinctive roles and promises that relate to each person of the Trinity. This liturgy declares what baptism means and what baptism promises to the people of God, not what the water of baptism accomplishes in each person baptized. In baptism, God the Father promises that He “makes an eternal covenant of grace with us and adopts us for his children and heirs.” In baptism, God the Son promises that He “washes us in His blood from all our sins, incorporating us into the fellowship of his death and resurrection, so that we are freed from our sins and accounted righteous before God.” In baptism, God the Holy Spirit promises that He “will dwell in us, and sanctify us . . . till we shall finally be presented without spot among the assembly of the elect in life eternal.” These promises in baptism declare the heart and center of our gospel hope. Baptism is not simply an external ceremony or simply the action of the church or of a believer.