Nasai

(1) The Mothers of the Believers and the Messenger of Allah (sallallahu alayhi wa sallam) themselves used to use blankets. Furthermore, this hadith also indicates that one should exercise caution when praying in clothes used by women and children, as well as other garments about which there is a suspicion that they may contain impurity or filth. This is because avoiding doubtful matters and basing actions upon certainty is what the Shari‘ah requires.

(2) One wisdom behind not praying in blankets and similar items could be that blankets are generally heavy and cannot be washed quickly. Therefore, if any impurity gets on them, it remains for a long time, while they are used daily. There is also a possibility of impurity occurring at the time of intercourse, so generally, one should avoid using such blankets that are placed on top during prayer times. And Allah knows best.

(3) If one is certain of the blanket’s purity, then prayer is permissible. The aforementioned hadith mentions a general matter, that most of the time, care is not taken regarding this. The Messenger of Allah (sallallahu alayhi wa sallam) would pray in garments used for intercourse when they were clean. Similarly, revelation would descend upon the blanket of Aisha (radi Allahu anha).