The bit of the post I found most helpful was Will's pointing out that the final hope of the Christian is not that we "go to heaven" as disembodied individual spirits but rather that God has promised that he will bring about a New Creation into which all people will be resurrected.
From this, Will concludes:
It is to this new creation that Christians point, and in doing so we, by the Holy Spirit, bring God’s new creation in spots around the world. Mission, then, is the work of the Holy Spirit bringing in bits of what God will do definitely when Jesus returns at the final resurrection. Mission is spreading the gospel (good news) that Jesus is the world’s true king, and that announcement does in some since divide the world into those who would accept it and those who won’t.A really good post and well worth a read.