"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.'" (Using translation from Nasāʾī 1711)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ «الْوِتْرُ حَقٌّ فَمَنْ شَاءَ أَوْتَرَ بِخَمْسٍ وَمَنْ شَاءَ أَوْتَرَ بِثَلَاثٍ وَمَنْ شَاءَ أَوْتَرَ بِوَاحِدَةٍ»  

[Machine] "Whoever wishes to perform the Witr prayer with seven (units), and whoever wishes to perform it with five (units), and whoever wishes to perform it with three (units), and whoever is unable should make an indication (with his hand)." Abu Abdur Rahman Al-Mawquf said, "The one stopped has the most correct opinion, and Allah knows best."  

«مَنْ شَاءَ أَوْتَرَ بِسَبْعٍ وَمَنْ شَاءَ أَوْتَرَ بِخَمْسٍ وَمَنْ شَاءَ أَوْتَرَ بِثَلَاثٍ وَمَنْ غُلِبَ أَوْمَأَ إِيمَاءً» قَالَ أَبُو عَبْدِ الرَّحْمَنِ الْمَوْقُوفُ أَوْلَى بِالصَّوَابِ وَاللهُ أَعْلَمُ