The Messenger of Allah ﷺ said, "When one of you wakes from sleep and wishes to perform ablution, let him not dip his hand into the water until he has washed it, for he does not know where his hand spent the night or what it touched."
حدثنا إسمعيل بن توبة حدثنا زياد بن عبد الله البكائي عن عبد الملك بن أبي سليمان عن أبي الزبير
قال رسول الله ﷺ إذا قام أحدكم من النوم فأراد أن يتوضأ فلا يدخل يده في وضوئه حتى يغسلها فإنه لا يدري أين باتت يده ولا على ما وضعها
[hasan] Daraqutni recorded it in his Sunan, 1/48, no. 125, from the hadith of Ziyad bin Abdullah Bakkai, transmitted through him, and he said the isnad is hasan. Busiri said, this isnad is sahih, its narrators are trustworthy, but Abu Zubayr Makki is well known for tadlis (Tabaqat al-Mudallisin, third rank), and he narrated it using an ambiguous form of transmission (an). The hadith also has corroborating narrations.