A very very long time ago, before most people were born (but not that long ago that there weren't any people), among the people that were alive at that time, there was a quiet, brooding guy. This guy wasn't necessarily evil, although he was always about logic and making sense that he wasn't popular with most other people. The reason is most people do stupid things and act according to what they feel like and disregard the consequences, but that is what everybody does, so it's ok, but not for him. According to him, he wouldn't hesitate killing a little girl to save more than one other life.
Until one day, he met a very cute girl, and they fell in love. This girl was the typical nice girl, and took time to understand his logic but also explained to him why sometimes its not always about logic, for example people would do stupid things for the ones they loved, and it wasn't as stupid as it would seem, in fact it would be a brave or romantic thing to do. Slowly this guy starts to understand what the cute girl meant, and every now and then he'd do some silly things that made the girl swoon.
By a unfortunate turn of events, though, this guy came into some sort of position of power. Meanwhile, the girl died, the consequence of some selfish act by a typically selfish person. Having lost his most important thing in the world, he became extremely depressed.
Through some weird cause and effect, the guy was asked to make a choice, regarding the lives of all the people in the world. Having just experienced a selfish act from another person who cause the life of his beloved cute girl, his choice was clear. Looking at all the selfish human beings, what worth is there left in this world?
Just at this moment a little man stepped out. He explained that he and his wife was about to have a baby, in less than a week, and pleaded our main guy to just postpone apocalypse for that amount of time. This little man was a hardworking and honest man, and nobody would have the heart to ignore his request. Soon more requests flooded in, and our main guy had a hard time deciding whether to end the world or not. This was because among the honest requests, there were people who lied, and they weren't very good at lying. Every now and then, the guy gets touched and was about to stop the apocalypse, then right at the next moment another selfish guy appears and makes him want to end it once and for all.
Seeing our main guy having such a hard time deciding, the cosmic entity who proposed the choice to him decided to give him as much time as he needed to make the ultimate choice. Because nobody could stand outside for so long, our quiet guy them proceeds off to his little hut, and sits down to brood it over.
People started sending requests to him through the mail, etc. Requests came in from all over the known world at that time, but less people visited him as the time passed. Despite earlier mentioned that he wasn't exactly the nicest guy around, he still made it a point to read all the letters.
Many years passed, the guy still couldn't decide. People were starting to get complacent, although they still contacted him they just did so as a daily mundane thing. They also got their children to do so, because little kids are adorable and make people go soft, and their children got their children's children and so on.
Soon after, people started to get even lazier. They invented something called praying, which is imagining that they have telephatic powers to communicate with him and they start to just "think" the request to him. The cosmic entity returned, and see the poor guy being hindered on all the information he needed to make his ultimate choice, gave him the power to listen in when everyone tried to "pray".
Generations passed, and the guy was still trying to make his choice, while the people slowly forgot about their lives in peril. The guy became something ancient, which people knew less of, and exaggerated more. Some way or another, "requests" because personal requests, and people ask him for a blessed life, joyful family etc, thinking that it would come true. In some way it help, people who believed that it would work subconsiously worked harder to achieve what they requested for.
Today, there's all the hoopla about him. Mistranslation and miscommunication made him into some creator of the universe, who has infinite power and could bring us all to a wonderful place. Although it may not be true, it has a positive effect on the people who believe in him.