Many religions began as a small group of people who held the same beliefs, and much of what they looked forward to was the promise of paradise after death. They saw the suffering of this world as a test to see if they would be good enough to ascend to a better place, and that is still true today. Almost every religion that has survived continues to promise that good behavior will mean a person is allowed into a place where their worries and fears will be abolished, and they will want for nothing.
It might seem in modern times that this type of promise is nothing more than a device to control large populations, and it has often been used in that way. Many countries over the centuries used religion to control their people, and they found it was a successful course of action. Most issues with a state supported religion only cropped up when the religious leaders had a disagreement with those who ruled the government.
The reward of religion has long been withheld until after the end of the current life, and it has been a successful way to help people survive through the trials of their current existence. In a world where only those who were born into wealth and privilege, there is still a path to a place where everything is perfect. It is a place where everyone is equal before whatever deity controls it, and even the poorest and least educated have the ability to attain entrance.
Few of even the most desperate people were willing to give up their chance to enjoy the bounties of the next life, and many of them spent their entire lives trying to ensure they would get there. Today, people continue to struggle to maintain a lifestyle that will lead them to the eternal pleasure and riches that can be theirs if they just survive this life with a record of good behavior within their religion.