Dealing with a difficult and combative person ?

I am not religious so I hope you don't mind me answering. I have dealt with people in my life who were like this. If they are hurtful to you, there's no better medicine then to tell them exactly how you feel when they mistreat you. Of course, do it in the most constructive manner possible. Somebody has to be the mature one in this situation. If they respond in a negative manner and continue the abuse, let them know you wont tolerate this and if it means separating yourself from them until the situation gets better then so be it. You cannot change a person. They have to do that on their own (and be willing to do it). I just can't see myself being around a person who affects me negatively. I'm sorry I couldn't give any better advice.