Ruling on intentionally missed prayers and Ramadan fasts?

Thank you for your question! 

As per our imams, one is to make up any missed prayers and fasts in addition to sincere repentance. This is because the making it up is a form of repentance. Sayyid Imam al-Qasim Rassi , upon him be peace, has stated in his treatise, Kitāb al-‘Adl wa at-Tawhīd:

If one is intentionally negligent regarding the prayer, fast, pilgrimage or purification dues—after it has been made obligatory upon him—due to frivolity and making light of it, it is religiously obligatory for him to repent to Allah for that. He must make up what he missed of the prayers and fasts if he knows their numbers. If he does not know how many, he is to calculate it as accurately as possible and exceed it. Then, we hope that there is no harm in either excess or slightly less as long as the person is not intentional in that.He can make up these prayers anytime he wants—whether day or night. If the times of his regular daily prayers occur, he is to pray them and then return to making up [his missed prayers]. He should not be engaged in anything else.

And Allah knows best!

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