Hadith 215
Ubayy bin Kaab said: The verdict that water (bath) is necessary when there is emission given by the people (in the early days of Islam) was due to the concession granted by the Messenger of Allah in the beginning of Islam. He then commanded to take a bath (in such a case). Abu Dawud said: By Abu Ghassan is meant Muhammad bin mutarrif.
Hadith 425
Narrated Abdullah ibn Sunabihi: Abu Muhammad fancies that witr prayer is essential. (Hearing this) Ubadah ibn as-Samit said: Abu Muhammad was wrong. I bear witness that I heard the Messenger of Allah ﷺ say: Allah, the Exalted, has made five prayers obligatory. If anyone performs ablution for them well, offers them at their (right) time, and observes perfectly their bowing and submissiveness in them, it is the guarantee of Allah that He will pardon him; if anyone does not do so, there is no guarantee for him on the part of Allah; He may pardon him if He wills, and punish him if He wills.
Hadith 1431
Narrated Abu Saeed al-Khudri: The Prophet ﷺ said: If anyone oversleeps and misses the witr, or forgets it, he should pray when he remembers.