The Messenger of Allah ﷺ said, "The eye is the drawstring of the anus, so whoever sleeps must perform ablution."
حدثنا محمد بن المصفى الحمصي حدثنا بقية عن الوضين بن عطاء عن محفوظ بن علقمة عن عبد الرحمن بن عائذ الأزدي
أن رسول الله ﷺ قال العين وكاء السه فمن نام فليتوضأ
Its isnad is daif. Abu Dawud reported it in the Book of Purification, chapter on wudu after sleep, hadith no. 203, from the hadith of Baqiyyah, through Ibn Aaidh, from Ali, as a mursal narration, as Abu Zura and Abu Hatim stated. It has a daif corroborating witness, and it has other corroborating witnesses as well.