16 Then the eleven disciples went to Galilee, to the mountain where Jesus had told them to go. 17 When they saw him, they worshiped him; but some doubted. 18 Then Jesus came to them and said, “All authority in heaven and on earth has been given to me. 19 Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”
If you skip to verse 19 (as many Christians do) you miss the powerful statement Jesus makes in verse 18: "All authority in heaven and on earth has been given to me." It's also true to that Jesus has always had "all authority" (i.e. Colossians 1:15-20 and John 1). The Jesus the disciples had known has now taken His rightful place alongside God the Father. He reminds the disciples that to encounter Jesus is to encounter God Himself.
1. Invite people into a growing relationship with Jesus Christ, 2. immerse them in the truth of who God is ("baptizing them" includes both the ritual of baptism and the call to introduce them to all of who God is) and 3. to invest in their lives by teaching them to obey Jesus.
Jesus assures us that we will not be alone in our efforts. He will always be with us to guide us, help us, reveal truth to us and lead us as we carry out His calling in our lives.