I've been thinking the last little while around " missional " as being the gene that identifies a faith community. The local faith community is in essence a band of missionaries, and that church and mission are interwoven. So interwoven, that you can not take them apart. The faith community that succeeds in unraveling mission from it's genetic identity...has become a mutation of something far less than Jesus imagined.
An old pilgrim who had worn out many pairs of shoes in the mission field once said, " There is no participation in Christ without participation in his mission to the world." If your in Christ, your in the world...this crusty sage left little room for negotiating.
Mission cannot be something separate from or added to the essence of a faith community. The essential nature that identifies the local faith community is, in and of itself, mission. Dietrich Bonhoeffer said it best when he noted that, " the church is the church only when it exists for others." This is most prominent when the church is engaged in mission, for being engaged in mission the church lives out its very nature and essence...the called out people of God calling out others to join them in the mission of God.
Johannes Blauw said some years ago, " it is exactly by going outside itself, that the church is itself."