—may Allah be pleased with them both—and several scholars have graded it weak. Even assuming it is authentic, all it says is:

“When the eyes sleep, the drawstring comes loose.”

This indicates that it is ordinary sleep that causes the drawstring to come loose. Yet the loosening itself does not invalidate ablution; rather, it is what comes out when it loosens that invalidates it. A person may relax until the drawstring comes loose without his ablution being invalidated.

As for the wording in the hadith of Safwān ibn ʿAssāl:

“We were commanded not to remove our leather socks when on a journey—or travelling—for three days and nights, except in a state of major ritual impurity, but not because of defecation, urination, or sleep.”

This does not state that sleep invalidates ablution. Rather, it states that someone wearing leather socks should not remove them for three days except because of major ritual impurity, and should not remove them because of defecation, urination, or sleep. It thus prohibits removing them for these reasons, and includes sleep that invalidates ablution. It does not state that every kind of sleep invalidates ablution. This is so even if the word “sleep” was spoken by the Prophet, may Allah bless him and grant him peace. How much more so if it was the narrator’s wording?

The Prophet, who conveyed the divine law, would have known that people sitting or standing, whether in prayer or otherwise, may become drowsy and fall asleep. Yet he did not instruct anyone to perform ablution in such cases.

As for ablution after what people ordinarily recognize as sleep, this concerns sleep during which passing wind is generally more likely. But sleep during which one may or may not pass wind does not invalidate ablution according to the principle held by the majority. They maintain that when one doubts whether ablution has been invalidated, it remains valid, on the basis of the established certainty of ritual purity.