Our Creator who blessed us with the gift of intelligence invites us to use this ability carefully several times in Quran (6:126, 21:10, 23:80, ...). Even though this may sound naturally expected, not doing so happens to be at the core of the beliefs of people and what they do and why. Best trick clergy has always used is taking the freedom of thinking away from their followers which makes them ready to believe in whatever they preach without questioning. Their most common lie is that faith is about choosing to believe or not, and that it is not about seeking the truth about God for real by finding actual evidences and gaining sureness about it. In Quran, even a messenger who even experienced miracles wishes to see proof that God can bring the dead back to life (2:260), because we are intelligent beings and things about the beyond are hard to comprehend and accept for our minds. But the good thing is God is aware about this and promises to show us signs so we can actually get to know (27:93).