The Prophet ﷺ said, "If any of you sleeps with the smell of grease still on his hand and does not wash it, then something harms him, he has only himself to blame."
حدثنا محمد بن عبد الملك بن أبي الشوارب حدثنا عبد العزيز بن المختار حدثنا سهيل بن أبي صالح عن أبيه
عن النبي ﷺ قال إذا نام أحدكم وفي يده ريح غمر فلم يغسل يده فأصابه شيء فلا يلومن إلا نفسه
[Sahih] Reported by Abu Dawud, Foods, chapter on washing the hand after food, no. 3852, from the hadith of Suhayl, and it is in his juz, no. 33. Ibn Hibban graded it sahih, no. 1354. The hadith has other versions with Tirmidhi, no. 1859, 1860, and Hakim, 4/137, and others, and this only strengthens it further.