Matthew 28:18-20 Jesus left the disciples with these last words of instruction: they were under His authority, they were to make more disciples; they were to baptize and teach these new disciples to obey Christ; Christ would be with them always. In previous missions Jesus had sent His disciples only to the Jews, their mission from now on would be worldwide. Jesus is Lord of the earth, and He died for the sins of people from all nations.
Matthew 28:19 Jesus' words affirm the reality of the Trinity. Some people accuse theologians of making up the concept of the Trinity and reading it into Scripture. As we see here, the concept comes directly from Jesus Himself. He did not say baptize them into the "names", but into the name of the Father, Son, and Holy Spirit. The word "Trinity" does not occur in Scripture, but it well describes the three-in-one nature of the Father, Son, and Holy Spirit.
Matthew 28:19 The disciples were to baptize people because baptism unites a believer with Jesus Christ in his or her death to sin and resurrection to new life. Baptism symbolizes submission to Christ, a willingness to live God's way, and identification with God's covenant people.
Matthew 28:20 How is Jesus with us? Jesus was with the disciples physically until He ascended into heaven, and then spiritually through the Holy Spirit (Acts 1:4). The Holy Spirit would be Jesus' presence that would never leave them. Jesus continues to be with us today through the Holy Spirit.