How to handle the boss who is very religious

My boss goes to a Baptist church, and he is very religious. I have been working for him more than 3 years. About 2 months ago, he brought me a pamphlet from his church and wanted me to read it. Today, he asked me whether I had read it in the middle of the review(my review went well) and wanted to treat me for lunch and talked about it. I replied I brief read it and we have our own church to go to. He said he understood it. After some talks, he came back to this topic again and said he considered me as a friend that is why he wanted to talk with me and he still wanted to go to lunch and just asked several questions. I was not sure how to reply and kept a silent. I like what I am doing now, don’t want to lose it, however I don’t want to start this kind of topic either. What should I say if he asks again? Is there a better way to handle this? Any advice is welcome. Thanks in advance.