A scripture on the mission of church; Jesus promises power to those who spread the good news of the kingdom:
But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth. (Acts 1:8)
From Article 10 of the Confession of Faith from a Mennonite Perspective:
We believe that the church is called to proclaim and to be a sign of the kingdom of God. Christ has commissioned the church to be his witnesses, making disciples of all nations, baptizing them, and teaching them to observe all things he has commanded.