Question:
assalamuallykhum is there any conclusive proof from quran or sunnah on weather fasting would be accepted or not if the muslim is not praying the obligatory prayers while fasting ?
Fatwa:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Any person who abandons the prayer while denying its legitimacy goes out of the fold of Islam according to the consensus of the scholars . There are absolute evidences that the acts of worship of a non-Muslim are not accepted. Allah Says (what means): {And what prevents their expenditures from being accepted from them but that they have disbelieved in Allah and in His Messenger.}[Quran 9:54]. Allah also Says (what means): {The example of those who disbelieve in their Lord is [that] their deeds are like ashes which the wind blows forcefully on a stormy day; they are unable [to keep] from what they earned a [single] thing. That is what extreme error is.} [Quran 14:18].
As regards a person who abandons the prayer out of laziness, then we do not know an absolute evidence which states that his fasting is not accepted; this depends on the ruling of abandoning the prayer. According to the view of some scholars who are of the opinion that a person who abandons the prayer goes out of the fold of Islam, then the above ruling applies to him. On the other hand, the scholars who are of the opinion that a person who abandons the prayer is not out of the fold of Islam, did not state that his fasting is not valid.
For more benefit, please refer to Fataawa 85264 and 83368.
Allah Knows best