Islam & Christianity: Inter-Faith Harmony

Suppose a person is living in an isolated island and he has tasted only bananas in his whole life. Although he has heard about other fruits like mangoes, apples and grapes, he has never tasted them. If he claims that banana is the best fruit on this planet, his claim is not based on any logic or rational because he has never tasted other fruits in this world. Similarly, people follow the religion of their parents, and they consider that their religion is right and superior, and all other religio