The starting place of Christian theology is found in the written records of the Gospels. The content of Christian theology is found in the whole Christian Bible; however, its method could be understood in the act and language of Baptism. God’s self-revelation found in Scripture is the basis and the foundation of Christian Theology. Baptism is an accurate summarization of this field of study. A detailed explanation of this act and language is found at the very end of the Gospel of Matthew.
The written records of the Bible, however, is a scope too great for us to summarize in one or two sentences. The Westminster Confession of Faith clearly asserts that “all things in Scripture are not alike plain in themselves, nor alike clear unto all” (I. VII.), yet some things are necessary to be revealed not only to Bible scholars but also to the simplest and most ignorant of the saints. So it is believed that Matthew 28:18-20 provides a detailed summarization of the Bible so that all can properly understand and apply Christian theology in their own lives. The “Great Commission verse” is not a detailed explanation of all purposes and ends of the Christian life, but a rough command of the mission that Jesus’ disciples are to obey. That being said, it follows that the starting point of Christian theology is by agreeing and acknowledging that what is written is “the Lord’s command,” not man’s (1Cor. 14:37 [HCSB]).
By this understanding, the Christian ought to pledge alliance to this command, therefore presenting himself as one who is striving to obey the words of the God incarnate, which are to “be kept diligently” (Ps. 119:4). The individual, then, is absorbed into this task by immersion in the waters of baptism. To be baptized is to “ἐξομολογέω”, that is, to confess openly and joyfully that he is part of the Christian family, therefore committing himself to the Christian mission, promising faithfulness to the one and only God, and agreeing with the Christian statements of faith that he verbalizes in the act of baptism. To confess in the act of baptism is to recognize that he was bought with a payment of blood by his New and Holy Master, and now is a slave of God (c.f. 1Cor 7:23).
The language of baptism symbolizes one’s death to his old self and life to one’s new identity. The old has passed away, and new things have come (2Cor. 5:17), is what is declared in that act. A burial, however, is not a good description of the language of baptism, for not many people are buried into the waters. Noah and Jonah are of great usage here. Noah’s flood represented death, Jonah’s story represents life, for he was brought to life after coming out of the waters. What baptism is symbolizing is: when one is immersed in the waters he is declaring his death and the judgment that he should receive, and when he comes out he is symbolizing the life that has been given to him by the same God who paid his deathly debt. The Christian, already out of the water is now ready to fulfill the vows that were professed before his baptismal act.
In one single act is declared (1) allegiance to the Triune God by confession; (2) death to the old self and old passions by immersion; and (3) what Christ did on the cross, atoning for his sins and
bringing him into the Christian community. Therefore, the act and language of baptism are and asserted explanation of the first step into the task of Christian theology. His theology, that was before confessed may now be lived out, proclaiming God’s glory to “all nations” (Mat. 28:19).