It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "Whoever sleeps at night with greasy hands and then something bites him, he should blame only himself."
Hadith Referenceالادب المفرد / كتاب / 1220
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : أخرجه أبوداؤد ، كتاب الأطعمة : 3852 و الترمذي : 1860 و النسائي فى الكبرىٰ : 6887 و ابن ماجه : 3297 - أنظر الصحيحة : 2956»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: From these narrations, it is understood that before sleeping at night, if there is any greasiness or the like on the hands, one should wash them so that no harmful thing is attracted by the smell of food and causes harm.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1220