A universalizing religion is one that states it applies to all of the people in the world and therefore is always looking to convert people to gain new followers. The three main universalizing religions are Islam, Christianity and Buddhism, according to Montgomery Country Community College.
A universalizing religion is also always available to all people regardless of their nationality, race or prior religious convictions. This is why they are called "universal," writes Montgomery Community College. Ethnic religions, on the other hand, will only allow membership into the religion at birth or because a newcomer has decided to take on a complex way of living. A person cannot simply "decide" or "declare" that he or she is a member of the ethnic religion.