غسل اليدين عند الاستيقاظ
Washing the hands before dipping them into a shared water vessel upon waking from sleep.
إِذَا اسْتَيْقَظَ أَحَدُكُمْ مِنْ نَوْمِهِ فَلْيَغْسِلْ يَدَيْهِ قَبْلَ أَنْ يُدْخِلَهُمَا فِي الْإِنَاءِ، فَإِنَّ أَحَدَكُمْ لَا يَدْرِي أَيْنَ بَاتَتْ يَدُهُ
“When one of you wakes from sleep, let him wash his hands before putting them into a vessel, for none of you knows where his hand spent the night.” (meaning, not a literal translation)
This instruction is specifically about a shared water vessel used by multiple household members — the concern is contaminating communal water with whatever the hand touched during sleep, rather than a general statement about the hand itself being unclean. It reflects a household water-sharing context common at the time, where a single vessel served several people rather than each having separate washing water.
A directly hygienic instruction, cited by modern commentators as a striking early parallel to handwashing protocols in contemporary infection control. Ibn al-Qayyim discusses this alongside the broader theme of protecting shared water sources from contamination, a concern that recurs across several practices in the tradition, including covering vessels and tying waterskins, covered in its own entry.
Modern infection control guidance identifies contaminated shared water sources as a genuine transmission route for illness, and handwashing before touching shared surfaces or containers remains a basic recommended practice — the underlying logic of this hadith aligns closely with contemporary public health guidance, arrived at through an entirely different (scientific, germ-theory) framework.