"So if you are in doubt, [O Muhammad], about that which We have revealed to you, then ask those who have been reading the Scripture before you. The truth has certainly come to you from your Lord, so never be among the doubters"(Qur'an,10:94) Means we need to ask an Imam or someone who has read before us,unlike what claims I've seen being made on countless Islamophobic sites saying "Muslims shouldn't doubt their faith,orelse they will die" and resort to name calling once proven wrong,it is very much a baseless claim without Sources or anything at all,not even an hadith.