Does a smoker remain under God's protection if he prays Fajr, or does he forfeit it due to his smoking? And does he enter Paradise if he dies while under God's protection? What actions cause a servant to lose God's protection?

The hadith "Whoever prays the Fajr prayer is under the protection of Allah" is general, encompassing everyone who prays Fajr, even if they are disobedient, such as a smoker. The meaning of being "under the protection of Allah" is that they are in His covenant, guarantee, and security. It is a warning that no one should harm them, otherwise, Allah will punish whoever harms them. Some commentators believe that committing acts of disobedience might remove a servant from this protection, and that the protection primarily refers to the prayer itself, which necessitates security. Thus, whoever neglects it has broken the covenant. As for sins and acts of disobedience in general, they are among the reasons a servant is deprived of Allah's protection and care. The greatest of these is polytheism. Just as obedience is a cause for protection, disobedience is a cause for deprivation, abandonment, and affects the ease or difficulty of matters.