Jamie--
Not enough detail here for anyone to provide much of a prescription, but there are some principles to remember:
Prayer is a powerful thing.
You cannot abdicate your parental responsibilities just because your child says no, whether he's two or twenty. Simply blaming the devil will NOT help your son.
Don't get isolated. If you are physically afraid of your son, get large (enough) male backup for things that you decide must be done.
Don't enable ungodly behavior.
It makes a big difference how old your son is. If he's twelve, that's one thing. If he's seventeen, a whole different set of rules and strategies must be applied.
Get direct and qualified help, not online help. I know it's embarrassing to admit that one has a child who is out of control, but you need real people in real time. Strangers on a chat board (like me) can encourage you and pray for you, but we don't know enough to give specific advice and you don't know us well enough to know if you should take our advice.