Is it permissible to declare a person as a Kafir (disbeliever) before advising him regarding the blasphemous act he commits?
If such a sinful person has committed an act of Kufr (disbelief), his fellow should tell him that he has practiced an act of Kufr and advise him kindly. If the person does not abandon his acts of Kufr, the rulings of Kafirs (disbelievers) should be applied to them. Then, the threat of eternal punishment of hellfire promised to those who die as disbelievers awaits them. It is the duty of every Muslim to keep calm and refrain from reckless declaration of people as disbelievers until the evident truth is revealed.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.