I want you to imagine, for a bit, that you are an early christian writer and you are one of the elite that knows that christianity is all a big scam. So, you know that when people ask to see the miracles that confirm that you are speaking on behalf of a true deity, none will be forthcoming. Even worse, the true creator of the universe might send a prophet like Elijah is supposed to have been to expose that your fake deity is powerless and may back that prophet up with miracles. What do you do?
Well, the first part is fairly simple. You just tell people that no signs will be coming to the wicked who seek them. Sure, this is contrary to existing belief, in which the deity frequently uses miracles to draw people to him. But you can say that it is a "new covenant." The second part is a little more difficult. You don't want people leaving your little deception to follow the real deal. What to do? And then it hits you. You tell your marks that there is an imposter who performs lying signs and wonder in an effort to deceive even the saved. If they believe that, they will become so trapped in a prison of their own minds that they will never see their way out.