For those who get easily turned off by rules on arranging altar wood and cutting livers, sin is where things can start to get interesting. Especially when it comes to the unusual things that Leviticus classifies as sinful.
For a big clue that strange things are afoot, look carefully at what the Israelites are supposed to make a sin offering for. It starts off in a pretty obvious way: you screw someone over in a business deal—sin offering. But having to sacrifice animals for a sin offering when a woman has her period? What is this, the Middle Ages?
Actually, it's actually a lot earlier than the Middle Ages. But even then, it was a bit odd to think of natural bodily functions as sinful, which is a word usually reserved for violating one of God's laws.
The solution to this conundrum lies in Hebrew word for sin, khata. Basically, it's a way of saying that something's off. Cheating a customer? That ain't right. Blood leaking out of a body when everyone knows that blood belongs inside? Why, that ain't right, either.
In Leviticus, sin isn't always as bad as it sounds.