Things that you have to do or follow to advance spiritually.
Many people follow these rules out of fear, and 'because that is what you have to do'... but their internal programming, and the person they really are, feels differently. Why else would you have 'confessionals' for example, unless people couldn't do what they are told. This makes people feel bad that they can't follow the rules. In Christianity at least, they are told they have free will, so if they can't follow the rules, it must be their own choice, and thus they are a bad person. This keeps them afraid, feeling guilty, and under control.
True spiritual advancment isn't brought about through following anothers set of rules. It comes from working out what the right thing to do is within yourself, and following your own path.
Everyones path is different, just as everyones lives and experiences are different.
When everyone starts from a different point on a map, what use is someone else's set of directions?
If someone hasn't gotten to the point where they can follow their own code of conduct and honour, then no amount or telling them what to do is going to change who they are.
But i can see how it happened. Someone advanced, and did their own thing. Became enlightened.. and said to people "This is how i did it!" ... and many people thought they could get there too, if they did the same thing, so they followed the path.. Somewhere along the way, the original idea became corrupted, and others started using the teachings to control people, and to gain power. The original idea of spiritual fullfillment and advancement then just became a tool to control people, and keep them in line. And thus you get the Catholic church today.. Keep people feeling guilty, and you have them on a leash... Tell them that if they give money to the church, god will look favourably upon them... and you become very very rich.