This is a very touchy situation. I am very religious and my dear husband, now passed, always said that it is important that we be tolerant of other religions. Your sister is younger. She is not mature. My suggestion would be that you not engage in any discussions of religion with her. A person's religious belief is personal and deep. It is not a subject for debate. I am dating a wonderful man, my Pastor, who is very strict. Even he would never put in doubt anyone else's religion. So, you and I know the right thing. The problem is that your sister doesn't. What part are your parents playing? They should be the ones to explain the idea of tolerance to your sister. In the meantime, Read your Bible

  Explain to your sister:   Religion may be a tree with many branches but the problem is that each branch believes it is the TRUE branch. That is a valid belief or else the branch is wasting its time and energy. If it isn't the "true" branch it should be merging with that branch which IS the true one. Therefor the need for argument. The necessity to determine whether one's religion is the true one or not. What a waste of time to find out you've been swimming to the farthest shore when there was one a lot closer. Harmony will come, from arguing or otherwise, when we all come to the realization that ALL paths (Christian or otherwise) do lead to the Oneness of God. Some just take longer routes.   v Religion and church 1) The common purpose of religion is to aid the entity in its search for Truth. 2) Each entity's level of development and understanding is different. 3) It takes many different styles of religion to accommodate the growth needs of entities at various times. 4) The value of a religion can be judged by its operation and intended accomplishments. 5) Churches exist for the benefit of entities. 6) Churches are to religion what a bathtub is to water. 7) They allow the entity an opportunity to soak in the fellowship of like-minded entities. 8) Churches also allow an entity a method through which to share.     From my chosen path i stray, Yet my God ne'er turns away; For i have learned -- and understand, That where God is -- is where i am!  

Just don't bring the topic up. And if you're older than her, exercise some authority!! Why does she, younger and less mature, make you feel uncomfortable unless you feel you're doing something wrong? If you're old enough to make your own decisions, then just tell your sister she can believe what she wants just like you can believe what you want. Unless she's willing to have you impose your beliefs on her, then she shouldn't be so aggressive about this.