What differentiate buddha's teachings from other religion is that he lets you doubt on his own teachings. For example, in christianity or in hinduism, you can be forgiven for any other sin if you regret for it. But you'll definitely go to hell and never will be forgiven if you've doubt over your own god. I watched a documentary about it few weeks ago and it really amazed me. But buddha asks you to doubt and analyse before accepting anything blindly.