Sleep, then, is treated like a cause of ritual impurity, yet it does not carry the same force. Any genuine act of impurity—however little or much, minor or major—invalidates ablution without distinction, whereas a brief doze is excused and carries no legal consequence. The proof for this distinction is the Prophet’s statement: “The eyes are the strap of the rectum; when the eyes sleep the strap is loosed, so whoever sleeps must renew his ablution.”

By these words the Prophet ﷺ indicated that when sleep becomes deep and the eyes fully close, one can no longer be confident that no impurity has occurred; and in both religious and worldly matters, what happens most of the time forms the basis for rulings, while rare occurrences are not taken into account. Conversely, if a person experiences only light drowsiness—a passing doze—he is safe from impurity. At the very least, heavy sleep creates doubt about one’s ablution, and it is impermissible to commence the prayer without being certain of one’s ablution.

This is the position of Mālik and the majority of his companions. A further proof is the report of Anas ibn Mālik: “The Companions of the Messenger of Allah ﷺ used to wait for him for the prayer …”