What is the ruling on one who smokes and does not pray the prayers on time?

Smoking is forbidden (haram) due to the harm it causes, and a smoker must repent and quit. As for delaying prayer beyond its prescribed time, it is a great evil for which Allah has threatened woe upon its doer, as Allah Almighty says: "So woe to those who pray [But] who are heedless of their prayer." It is an appointed obligation, and delaying it is a grave sin that may invalidate one's deeds. Some scholars have even gone so far as to say that abandoning a single prayer is an act of disbelief (kufr).