Our Mission is not primarily ours. We are participants in the mission of God, following where he leads - and so we declare "It is not the Church who has a God of Mission, but the God of Mission who has a Church."
Mission is Evangelism - It is the spreading of the Good News of what God has done in Jesus Christ throughout the world. Through it, our actions are given purpose.
Mission is Service - It is the work of being the hands and feet of Jesus in the world around us. Through it, our words are given credibility.
One without the other is incomplete.