Hold on a second, here. Before you go off half-cocked, let’s try and figure out what it is that you really want and what your options are.
First: What is your legal status in this household? What is his legal status? Is he just some guy who is splitting the rent or are you both on the lease or what? That may come in handy to know.
Second: what do you really want to achieve, here? Do you want to get this guy to stop harrassing you? Do you want to convince him that you’re right and he’s wrong?
If I were you (and I’m not you), I would aim for an end to the harrasment. This is your HOME - you shouldn’t have to argue with people in YOUR HOME. You have a right to a happy, stress-free home. That’s a fact. In fact, I’d be willing to bet that what he is doing could be illegal, under certain circumstances.
You cannot change every person’s mind. Sometimes, it’s worth the bother to argue. But, I wouldn’t do that in my own home. There will be countless other mislead souls to argue with in life.
So, if I were in your position, I would decide, first, not to argue any longer. Then, I would tell him, “I do not want to argue about religion with you any more. Please stop bringing up the subject of my religion.” If he does it, tell him, “I have a right to my beliefs and to be treated fairly in my own home. What you are doing disturbs my peace. Please stop.”
I am not sure what you should do if he will not, but I think you may have a legal right to kick him out of your apartment, even if he is on the lease.