"Those who had been baptized devoted themselves to the apostles' teaching and fellowship, to the breaking of bread and the prayers."
I guess there is some debate as to whether the Church described in Acts 2:42 was actually the early Church or just the ideal to which it aspired. Either way, it continues to be the the fullest description of how the contemporary Church, in all of its variations and forms called churches, should live out its mission.
We are called to teach and be taught.
We are called to fellowship.
We are called to break bread.
We are called to pray and be prayed for.
Emil Brunner has famously said, "The Church exists by mission as fire exists by burning" and while I don't disagree with the famous Swiss Reformed theologian, I tend to think that Mission comes as a natural side effect of hearing the lessons of Jesus' life and ministry, seeking to share the joy that comes from Christian fellowship, receiving the grace of God's Holy Communion, and earnestly desiring God's will for ourselves and the rest of God's good creation.
Taking Brunner's analogy to the edge of its usefulness, if fire requires fuel, heat, and oxygen to produce a flame then the Church needs teaching, fellowship, breaking bread, and prayer to produce mission. When one is lacking, the focus turns wrong way in, and the problem isn't a lack of mission, which tends to get the attention. Instead, it is almost always a lack of prayer or a hubris against education, or a lack of fellowship. At least in The Episcopal Church there's never a lack of bread breaking. ;-)