Bulugh al-Maram 1 The Book of Purification كتاب الطهارة 44

وَعَنْهُ: { إِذَا اِسْتَيْقَظَ أَحَدُكُمْ مِنْ نَوْمِهِ فَلَا يَغْمِسُ يَدَهُ فِي اَلْإِنَاءِ حَتَّى يَغْسِلَهَا ثَلَاثًا فَإِنَّهُ لَا يَدْرِي أَيْنَ بَاتَتْ يَدَهُ } مُتَّفَقٌ عَلَيْهِ. وَهَذَا لَفْظُ مُسْلِم ٍ 1 . 1 – صحيح. رواه البخاري (162)، ومسلم (278).

Narrated Abu Huraira (rad): Allah’s Messenger (صلى الله عليه وسلم) 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)”. [Agreed upon. This is Muslim’s version].