Conclusive proof of God

[Aoi Magi]

Believers are skeptic, towards all other religions except their own. Only those who are willfully ignorant cannot be swayed.

Its hard to accept other beliefs only when they contradict with your own. Muslims believe part of the Bible and vice-versa.

Nothing happens overnight, and beliefs wont change right away either. Everyone who isn't being willfully ignorant, do change their beliefs over time. Most muslims don't practice the violence prescribed in their scriptures, same goes for other religions. All have adapted to the changes in society, and if a real god comes to earth and proves himself, people will change their beliefs easily.

A little beating, or free food has already converted entire countries to a specific religion. If a supernatural being appears who can create and destroy planets at whim, gives away free food and free energy, then the existing believers would be the first in line to convert.