Jesus now sends the disciples to make disciples of all nations. That does not mean make everyone disciples. Most people who are helped by Jesus and believe in him never become disciples. Jesus includes in salvation people who do not believe in him or even know about him. Disciples are students, called for the sake of the world to learn from Jesus and to bear witness to the kingdom.
Makes sense to me but apparently this is some sort of evidence the ELCA is going to hell in a handbasket. Erik Ullestad over at Koinonia went to the source and got an explanation from Dr. Priebe himself. It's worth a read!