This is even more emphatically recommended when a person wishes to sleep while in a state of janābah (major ritual impurity).

Wuḍūʾ after every minor impurity

Buraidah ibn al-Ḥuṣayb relates that the Messenger of Allah ﷺ awoke one morning and summoned Bilāl, saying, “Bilāl, by what deed have you preceded me to Paradise? I entered Paradise and heard the rustling of your footsteps ahead of me.” Bilāl replied, “Messenger of Allah, I have never called the adhān without then praying two rakʿahs, and no minor impurity has ever befallen me without my performing wuḍūʾ right away.” The Messenger of Allah ﷺ said, “It is because of that.” This was recorded by Ibn Khuzaymah in his Ṣaḥīḥ, and by Tirmidhī, Muslim, and Aḥmad (sound). See al-Targhīb 1/99.

He ﷺ also said, “No one preserves his state of wuḍūʾ except a believer.” (Muslim, Aḥmad, Ṭabarānī – sound). See al-Fatāwā 2/424–425.

Wuḍūʾ before the full bath

Wuḍūʾ is prescribed for the one who carries a corpse, for the Prophet ﷺ said, “Whoever washes a deceased person should bathe, and whoever carries him should perform wuḍūʾ.” It was reported by al-Ṭayālisī (305) and by Aḥmad (2/454) through the chain of Ibn Abī Dhiʾb, from Ṣāliḥ, the freedman of al-Tawʾamah, from Abū Hurayrah.

This chain is considered ḥasan by some scholars, and Ṣāliḥ, the freedman of al-Tawʾamah—though spoken against—is not the sole transmitter of the report. Aḥmad (2/272) also narrated it from Ibn Jarīr, who said, “Suhayl ibn Abī Ṣāliḥ told us, from his father, from Abū Hurayrah,” and this chain is ṣaḥīḥ according to Muslim’s criteria.

Sufyān, however, differed and said, “from Suhayl ibn Abī Ṣāliḥ, from his father, from Isḥāq, the freedman of Zāʾidah, from Abū Hurayrah….” Abū Dāwūd recorded it (2/63), thereby inserting between Abū Ṣāliḥ and Abū—