'we also speak, knowing that he who raised the Lord Jesus will raise us also with Jesus and bring us with you into his presence. For it is all for your sake, so that as grace extends to more and more people it may increase thanksgiving, to the glory of God.' (2 Cor 4:13-15)
Mission is founded on personal hope in the Gospel (v.14) and for the sake of
- the salvation of the lost, so that
- thanksgiving may increase, so that
- God is glorified.
So it is not simply an expression of personal joy, or simply to save people from hell, or even simply for God's glory. It is all of those, but in a certain relationship.
(cf. Romans 15)