When one of you wakes up from sleep, he should not dip his hand into the vessel until he has washed it three times, for he does not know where his hand spent the night.
حدثنا وكيع قال حدثنا الأعمش عن أبي صالح وأبي رزين عن أبي هريرة رفعه كذا قال
إذا استيقظ أحدكم من منامه فلا يغمس يده في الإناء حتى يغسلها ثلاثا فإنه لا يدري أين باتت يده
Its chain of transmission is sahih. It occurred previously at 7280 and 8944. Abu Razin is Masud bin Malik Asadi, their freedman, though it is said he was the freedman of Ali bin Abu Talib.