Hadith 453

‘Aisha said that when the Prophet was defiled and wanted to eat or sleep, he performed the ablution prescribed for prayer. (Bukhari and Muslim)

وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا كَانَ جُنُبًا فَأَرَادَ أَنْ يَأْكُلَ أَوْ ينَام تَوَضَّأ وضوءه للصَّلَاة

Reference: 5604530
In-book reference: Book 3, Hadith 453
Hadith 453 - Purification - Mishkat al-Masabih - Sunnah.com