A couple of things: Forums get pretty bad CTRs, you'll need to get creative and test so you can bring them up. You're getting a tiny cost per click because I'd imagine people aren't bidding high on a lot of religion keywords. Not too much money in it. Experiment with other monetization sources. What is your audience spending money on? You could affiliate with some online booksellers (like amazon) that sell religious books, or find someone who specializes in that niche that could give you a better rate than amazon. You could create some merch on cafepress with biblical sayings and advertise it on the forum.
65 dollars is pretty normal for Arabic and religion-related ads. Thats 3 cents per click. I bought a network of Eastern European non-English speaking web sites (so with non-English speaking ads), and i get 5 cents a click, and the niche is real estate/ personal loans. I suggest that you affiliate with religion-related and arabic language affiliate programs. You would make more money than with AdSense. Hope that helps.