When do we consider a person who has been judged as a disbeliever to be a disbeliever: is it from the time the ruling is issued, or retroactively from his act or statement of disbelief?

The judgment of a Muslim as an infidel is a serious matter, falling under the jurisdiction of the Islamic judiciary, and it requires the fulfillment of conditions and the absence of impediments. Not every act of disbelief leads to the excommunication of its perpetrator; rather, evidence must be established and doubts dispelled. Excommunication has conditions and impediments that might not be present in the case of a specific individual, just as duress prevents a ruling of disbelief if the heart is secure in faith.