The Great Commission for the Church, found in Matthew 28:19-20, consists of three parts: 1) Teach all nations. 2) Baptize those who believe. 3) Teach the new believers Christ's will for their lives.
1) The only message that the lost world needs to hear is the Gospel of Jesus Christ. It begins with the fact that God loves each one of us. He demonstrated His love by sending His Son (John 3:16) to die for us, to be buried, and to rise again, all according to the Scriptures (1 Corinthians 15:1-8). But, Christ paying for the sins of the world does not end the Gospel message. At the moment a person recognizes Christ's love for him, a change of attitude occurs called repentance. Salvation has two parts: the acceptance of Christ having paid for one's sin (Remission), and the change in attitude regarding obedience (Repentance). Jesus said that both were to be preached in Luke 24:47. When a person accepts the Lord, he has admitted that he is a sinner and needs a Savior; he acknowledges that Jesus paid for his sin, and he commits his life to serving Him as Lord.
2) The first step in obedience to Christ involves being baptized. The Church began at Pentecost when the Holy Spirit descended upon the first believers in Christ (Acts 2:1-3). Peter preached the Gospel to the crowd and three thousand accepted Christ, and were immediately baptized (Acts 2:41). The Ethiopian Eunuch was presented the Gospel and immediately was baptized (Acts 8:35-38). Notice baptism follows Salvation. Belief in Christ results in Salvation (John 1:11-13), and all who believed were baptized.
3) The next part of the Great Commission is a little more difficult to sum up in a short paragraph. It involves Christ's teaching on how one is to live in relationship with God, in relationship with other believers, and in relationship with the lost of the world. We are to love God with our whole being (Matthew 22:37). We are to love other Christians, our Brethren (1 John 3:14). We are to love the lost who are enemies of God, and therefore, our enemies (Matthew 5:43-48; Romans 5:10; John 15:18-23). All of these admonitions are covered by the Apostle Paul in his letter to the Galatians. He said, "For all the law is fulfilled in one word, even in this: Thou shalt love thy neighbor as thyself (5:14). In order to love everyone, one must first love God. The evidence that one is filled with God's Spirit is love (Galatians 5:22). That is the whole truth.