وَعَنْهُ: «إِذَا اِسْتَيْقَظَ أَحَدُكُمْ مِنْ نَوْمِهِ فَلَا يَغْمِسُ يَدَهُ فِي اَلْإِنَاءِ حَتَّى يَغْسِلَهَا ثَلَاثًا فَإِنَّهُ لَا يَدْرِي أَيْنَ بَاتَتْ يَدَهُ»
The Messenger of Allah (sallallahu alayhi wa sallam) said: “When one of you wakes up from his sleep, he must not put his hand in a utensil till he washed it three times, for he does not know where his hand was (while he slept)”.
Bulugh al-Maram 44, Book 1, The Book of Purification, Hadith 44. 1 min read