Muhammad was a good person and people were interested in what he had to say because it was different to what they knew, at least curious people were. Other people were not as interested and did not want to listen to Muhammad at all. The rich merchants thought he was a threat to their money, as he said the rich should take care of the poor, and cast him out. Since the poor people did as the rich people did, basically everyone started to stop listening to Muhammad. Overtime, however, people started to listen more and more until Islam was a religion. Islam is very similiar to Chistianity and Judisasm.