So, a long, long time ago, there was a group of people called the Israelites. They were led by a man named Moses and they believed in a powerful God who told them how to live their lives.
One day, while they were camping in the desert, some people in the group started to worship a God named Peor instead. Peor was a naughty God who liked it when people did bad things.
This made Moses and the other leaders of the Israelites very angry because they believed that worshipping Peor went against what their God had taught them. They were worried that if people kept worshipping Peor, it would cause problems for them later on.
So, they decided to punish the people who were worshipping Peor. They even put some of them to death! This was called the Heresy of Peor because it was a big deal to the Israelites that anyone would worship another God instead of their own.
In the end, the Israelites stopped worshipping Peor and went back to following their own God. And that's the story of the Heresy of Peor.