Prayer: Due to Past Masturbation and Occasional Janābah, Is Qadā’ of Missed or Invalid Prayers Obligatory?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: Due to Past Masturbation and Occasional Janābah, Is Qadā’ of Missed or Invalid Prayers Obligatory?

English:

Question #523:

Unfortunately, due to my ignorance and lack of will power I had got into the evil habit of masturbation, and so I did not perform prayers at times. But I do not know how long I abandoned prayers, as it was not one continuous period (I would not have prayed when I was junub until I took ghusl, although it may have been delayed for a while), but I think that it lasted for six months. I have made up my mind to perform the qaḍā’ of my prayers for this period. Is it obligatory to perform qaḍā’ of these prayers?

Answer #523:

You must perform the qaḍā’ of all daily prayers that you know you did not perform or you performed while you were junub.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer