Is one who made a covenant with his Lord to abandon a sin, then returned to it believing that the covenant was impermissible from the outset, deserving of punishment (entering Hell, abiding therein eternally)?

A Muslim must fulfill his covenants, most importantly what he has covenanted with Allah, especially the abandonment of sin. However, supplicating fire upon oneself is forbidden, and there is a fear that it might be answered, according to the Hadith: "Do not supplicate against yourselves..." Its apparent meaning is that the supplication might coincide with a moment of answer, yet eternal damnation in Hellfire does not befall monotheists. Some scholars have said that this type of supplication is idle talk, for which there is no accountability. We advise sincere repentance, seeking refuge in Allah, and abundant, persistent supplication to ward off evil, for indeed supplication repels affliction. The Prophet, peace and blessings be upon him, said: "Nothing repels divine decree except supplication," and "Indeed, supplication benefits regarding what has descended and what has not descended."