In Matthew 28:18, Jesus announces that all authority has been given to Him in heaven and on earth. With that authority, Jesus commanded those with Him to do one thing: make disciples. As he gave this command, Jesus answered three questions: when, who, and how.
When should they make disciples? As they are going. Even though the word “Go” reads like a command in English, it is better translated as “As you are going.” That they are going places is assumed. Jesus’ command to make disciples concerns what they should be doing as they move about on the earth. Furthermore, there is no indication that this command ends until they are no longer “going” on the earth; it extends as long as their physical lives continue. They would not fulfill their responsibility to make disciples until they passed from this earth.
Of whom should they make disciples? All the nations. All people on earth are the object of the mission of Christ. The inclusion of Gentiles was challenging for the Jews in Jesus’ time, who were accustomed to shunning all who were not Jews by ancestry (See Acts 13:45). “All the nations” means the Gentiles are to become disciples of Christ along with the Jews. Jews and Gentiles were to assume a new identity as followers of Christ, united in fellowship by His atoning sacrifice (See Ephesians 2:13ff).
How should they make disciples? By baptizing them and teaching them. Jesus presents baptism as a critical component of making disciples. Immersing a person in water in the name of the Father, Son, and Holy Spirit is prescribed. The phrase “in the name of” means “by the authority of,” as evidenced by Acts 4:7. Jesus’ point about baptism is not to give a script for those immersing prospective Christians. Instead, He emphasizes the authority by which a person becomes a disciple and is forgiven of their sins (See Acts 2:38). It is by the authority of all that is God that a person is made a disciple and forgiven of their sins at baptism.
The second part of making disciples involves teaching them all that Jesus commanded. That teaching consists of the entirety of the binding message of God. Of particular interest, it also includes this command to make disciples as you are going by baptizing and teaching the lost. Evangelism, then, is a perpetual command and mission for every Christian. Be about it, brethren!