Imams are Infallible
All the Imams are necessarily infallible and cleansed of all sins, petty or grave, committed intentionally or unintentionally, pertaining to sayings or doings, for if they committed sins, they would lose their position in the hearts of the people who would not have confidence in them. In such a condition how would they guide the straying and the misleading? There is a consensus of opinion that no one is infallible except the 12 Imams. Thus their leadership is an established fact.