Extracted lessons from the ḥadith:

1. Some narrations link this forceful expulsion of water from the nose (istinṯār) to the act of wuḍūʾ, making it an explicit component of ablution, while others mention it without any restriction. Hence, the preferable practice is to perform istinṯār three times when one wakes up from night-sleep and is not about to make wuḍūʾ, for it closely resembles washing the hands after rising from a night’s rest.
2. The ḥadith indicates the legitimacy of istinṯār, for it is phrased as a directive, and istinṯār necessarily entails inhaling water first (istinshāq).
3. The ruling is confined to night-sleep, inferred from the phrase “he spends the night,” because bayātah refers only to sleeping at night, when sleep is usually lengthy and deep.
4. The rationale given is that Satan spends the night upon one’s nasal passage. Qāḍī ʿIyāḍ said: This may be taken literally, for the nose is one of the body’s openings, and no other orifice besides the nose and the ears lacks a cover. The command to stifle a yawn was likewise given because Satan may then enter through the mouth.
5. The hadith urges caution regarding Satan, for he seeks every avenue into the child of Adam, flows through him like blood, and strives to misguide him and corrupt his worship. Thus the human being is ever pursued and besieged by him; only the one whom Allah protects, who seeks Allah’s help and refuge from his evil, is safe.
6. When such transmitted rulings are sound, the believer’s duty is to accept and submit to them even if he does not perceive their modality. The Almighty says: “And you have been given only a little knowledge” (17:85).
7. Shaykh al-Islām Ibn Taymiyyah held that washing the hands after waking from night-sleep and performing istinṯār on awakening are both due to contact with Satan. He explained the hand-washing by saying that one does not know where his hand spent the night, and he explained the nasal rinsing by saying that Satan spent the night on—