" Ibn Shihab informed me, saying: 'Ata bin Yazid narrated to me from Abu Ayyub: That the Prophet (ﷺ) said: 'Witr is a duty, and whoever wants to pray witr with seven (rak'ahs), let him do so; whoever wants to pray witr with five, let him do so, whoever wants to pray witr with three, let him do so; and whoever wants to pray witr with one, let him do so.'"
Sunan an-Nasa'i Book 20, Hadith 113
← Previous Hadith "The Messenger of Allah (ﷺ) used to pray nine (rak'ahs) at night, then when he grew older and put on weight he prayed seven."

Sunan an-Nasa'i Book 20, Hadith 112 Next Hadith → "Az-Zuhri narrated to me, he said: 'Ata bin Yazid, from Abu Ayyub: The Messenger of Allah (ﷺ) said: 'Witr is a duty, and whoever wants to pray witr with seven (rak'ahs), let him do so; whoever wants to pray witr with five, let him do so, whoever wants to pray witr with three, let him do so; and whoever wants to pray witr with one, let him do so.'"

Sunan an-Nasa'i Book 20, Hadith 114