النهي عن النوم على البطن
A specific discouragement of sleeping face-down, distinct from the existing entry on sleeping on the right side.
إِنَّ هَذِهِ ضِجْعَةٌ يُبْغِضُهَا اللَّهُ
“This is a lying position that Allah hates.” (meaning, not a literal translation)
Narrated after the Prophet ﷺ saw a man sleeping on his stomach in the mosque and woke him with his foot to say this — a directly observed correction of a specific individual, similar in structure to the hair-oiling account elsewhere on this site.
Commentators pair this with the existing 'Sleeping on the Right Side' entry as two halves of the same guidance on sleep posture — one positive instruction, one direct discouragement. Ibn al-Qayyim notes some scholars connect this specifically to prone sleeping's association, even in classical medicine, with restricted breathing and discomfort, though the hadith's stated reasoning is that Allah simply dislikes the position, not a stated medical rationale.
Modern sleep medicine notes prone (stomach) sleeping can strain the neck and spine and, in specific vulnerable populations such as infants, is a recognized risk factor discussed in SIDS prevention guidance — a genuine area of overlap, though the hadith's own stated reason is not medical.