Are Acts of Worship Waived for Anyone?
Question
It is well known about a certain elder among the pious that the Pure Lord excused him from His obligatory duties, and the Prophet ﷺ excused him from the sunnahs, on account of his afflictions and weakness. If this incident has come before you in any book, kindly write about it.
Answer
I do not recall having seen this specifically in any book, but the ruling itself is correct. It is this: if a person is so ill and weak that he can neither perform wudu nor tayammum, can pray neither standing, nor sitting, nor lying down, can perform neither ruku‘ nor even a gesture (ishara)
Source: Fatawa Mahmudiyya
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