Islam and Christianity; The Issue of " Either Ration or Faith?"

This Article investigates and compares Islam and Christianity meeting the issue of either ration or faith, and seeks to respond following questions: when we face religious statements, ration should be preferred or faith?How much credible is each of them? Have followers of other religions such as Christianity ever faced by such a problem? If so what did they do, and what is their viewpoints about ration and their definition of faith? And why did they side with ration or faith? What is the difference between thinkers on role of ration and faith in religion? And what solutions have been presented? Criticizing of proposed options and explaining of Islamic scientist’s faith and ration definitions, comparing them with findings of Christianity, demonstrating the difference between these two views, and finally presenting a definition of religion and using of its implications in order to respond above questions; is the intention of this essay.