OK - This is a silly and brief thought (brief because I am using a computer in a library and have few minutes left in which to write).
I always took the great commission in Matthew 28:19 to be Jesus telling the whole church (which included me) to go and convert everyone in the world. You know - the standard evangelical reading (not, I hasten to add the classical Christian reading - on which see the brilliant reception history study of the text by David Parris in Reading the Bible with Giants).
The more that I read the NT in the light of the OT the more crazy interpretations I keep coming up with.
So here is something I was wondering about (and I am no Matthew scholar) - What if we read the commission in the light of the OT story accoring to which God will restore Israel and then, through Israel, he will draw the nations to worship him? There is a strong case for seeing such restoration-of-Israel and mission-to-the-nations stuff going on in Matthew (see esp. Joel Willitts book on Israel's Shepherd King in Matthew - cannot recall exact title).
If we do this then Jesus is commissioning his disciples, as representatives of restored Israel, to take the good news of Israel's resotration and salvation for the world to the nations of the world.
I have always read it as a call to the church to go to the world. But if Jesus was calling restored Israel to go to the nations then the text's relevance for a mission by Gentile Christians to other Gentile Christians is one or two steps away from what Jesus was getting at. I am not wanting to say that the text is of no relevance for such contexts but simply that it may be of more indirect relevance than we may have thought.
I guess that I will now get lots of replies saying, "Everyone knew that anyway! You're slow off the mark" Yes I am. Better late than never.
So I guess my question is - what is Jesus commanding in Matt 28? Who is he commanding? How does it apply today?