The Great Commission is impossible, but Jesus gave a phenomenal promise that the Church can succeed: "Behold, I am with you always, to the end of the age" (Matthew 28:20), Christ's perpetual presence.
There are three implications of Christ's perpetual presence that allow us to proceed with the Great Commission with confidence:
1. Commission Impossible – we need help
2. Divine Supervision – we are not abandoned
3. Mission Accomplished – there is an end
Stylistic question: some people love audience involvement (aka. "repeat after me" or "turn to your neighbor and say..." etc.) and some people hate audience involvement. Is there a right way to do it? Should it be done at all?