"Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age" (Matthew 28:19-20).
The mission of the church includes making disciples. A disciple is a follower and a learner. In this case, these are followers of an learners about the God of the Bible. These disciples have a relationship with the Triune God and this is signified by baptism into his Triune Name.
It is also the mission of the church to teach observance of Christ's commandments. all he commanded is important. Thus, the teachers of the church must communicate the whole counsel of God. And the goal is not mere head knowledge, but heart transformation that results in changed lives.
This is the Great Commission and with it comes the Great Assurance that Jesus will be with his people. The spread of the gospel around the world, the maturing of disciples, the empowerment to teach, changed hearts eager to observe and obey, all come through the mighty working of our God who is always with us. And he will be with us to the end.