When discussing the purpose of religion, many people believe the purpose of religion is to answer questions. Questions such as:
One of the tasks of a human being is to discover
It can take one's whole life to answer these questions. That effort is large enough that humans look for a shortcut. Some structure they can believe will provide these answers. Some pre-made structure that helps them fit in and operate faster.
So the individual reaches out to a structure larger than themselves. Something external that can impose structure they find difficult to maintain on their own. That external structure is often a religious structure or a belief system.
Hence one purpose of religious belief system is to impose an external structure he individual utilizes to