The Messenger of Allah ﷺ came out to us and said: Allah the Exalted has given you an extra prayer which is better for you then the red camels (i.e. high breed camels). This is the witr which Allah has appointed for you between the night prayer and the daybreak. (Using translation from Abū Dāʾūd 1418)   

خَرَجَ عَلَيْنَا رَسُولُ اللَّهِ ﷺ فَقَالَ «إِنَّ اللَّهَ قَدْ أَمَدَّكُمْ بِصَلَاةٍ هِيَ خَيْرٌ لَكُمْ مِنْ حُمْرِ النَّعَمِ جَعَلَهُ لَكُمْ فِيمَا بَيْنَ صَلَاةِ الْعِشَاءِ إِلَى أَنْ يَطْلُعَ الْفَجْرُ»  

Ibn Muhayriz said: A man from Banu Kinanah, named al-Makhdaji, heard a person called AbuMuhammad in Syria, saying: The witr is a duty (wajib). Al-Makhdaji said: So I went to Ubadah ibn as-Samit and informed him. Ubadah said: AbuMuhammad told a lie. I heard the Messenger of Allah ﷺ say: There are five prayers which Allah has prescribed on His servants. If anyone offers them, not losing any of them, and not treating them lightly, Allah guarantees that He will admit him to Paradise. If anyone does not offer them, Allah does not take any responsibility for such a person. He may either punish him or admit him to Paradise. (Using translation from Abū Dāʾūd 1420)   

أَخْبَرَهُ وَكَانَ يَسْكُنُ بِالشَّامِ وَكَانَ أَدْرَكَ مُعَاوِيَةَ أَنَّ الْمُخْدَجِيَّ رَجُلٌ مِنْ بَنِي كِنَانَةَ أَخْبَرَهُ أَنَّ رَجُلًا مِنْ الشَّامِ وَكَانَتْ لَهُ صُحْبَةٌ يُكْنَى أَبَا مُحَمَّدٍ أَخْبَرَهُ أَنَّ الْوِتْرَ وَاجِبٌ فَرَاحَ الْمُخْدَجِيُّ إِلَى عُبَادَةَ بْنِ الصَّامِتِ فَذَكَرَ ذَلِكَ لَهُ فَقَالَ عُبَادَةُ كَذَبَ أَبُو مُحَمَّدٍ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ «خَمْسُ صَلَوَاتٍ كَتَبَهُنَّ اللَّهُ عَلَى الْعِبَادِ مَنْ أَتَى بِهِنَّ لَمْ يُضَيِّعْ مِنْ حَقِّهِنَّ شَيْئًا اسْتِخْفَافًا بِحَقِّهِنَّ كَانَ لَهُ عِنْدَ اللَّهِ عَهْدٌ أَنْ يُدْخِلَهُ الْجَنَّةَ وَمَنْ لَمْ يَأْتِ بِهِنَّ جَاءَ وَلَيْسَ لَهُ عِنْدَ اللَّهِ عَهْدٌ إِنْ شَاءَ عَذَّبَهُ وَإِنْ شَاءَ أَدْخَلَهُ الْجَنَّةَ»  

[Machine] An Arab man came to the Messenger of Allah ﷺ and raised his head, then he said, "O Messenger of Allah, what has Allah prescribed for me from the prayers?" The Messenger of Allah ﷺ replied, "The five daily prayers and fasting." The Messenger of Allah ﷺ informed him about the obligations of Islam, and he said, "By the One who has honored you, I will not do anything voluntary, nor will I decrease from what Allah has prescribed for me." The Messenger of Allah ﷺ said, "He has succeeded, and so has his father if he speaks the truth, or he will enter Paradise, and so will his father if he speaks the truth."  

أَنَّ أَعْرَابِيًّا جَاءَ إِلَى رَسُولِ اللَّهِ ﷺ ثَائِرَ الرَّأْسِ فَقَالَ يَا رَسُولَ اللَّهِ مَاذَا فَرَضَ اللَّهُ عَلَيَّ مِنَ الصَّلَاةِ؟ قَالَ «الصَّلَوَاتِ الْخَمْسَ وَالصِّيَامَ» فَأَخْبَرَهُ رَسُولُ اللَّهِ ﷺ بِشَرَائِعِ الْإِسْلَامِ فَقَالَ وَالَّذِي أَكْرَمَكَ لَا أَتَطَوَّعُ شَيْئًا وَلَا أَنْقُصُ مِمَّا فَرَضَ اللَّهُ عَلَيَّ فَقَالَ رَسُولُ اللَّهِ ﷺ «أَفْلَحَ وَأَبِيهِ إِنْ صَدَقَ أَوْ دَخَلَ الْجَنَّةَ وَأَبِيهِ إِنْ صَدَقَ »  

[Machine] I heard Ali saying, "Verily, Witr (a specific prayer) is not obligatory like the regular prayers, but it is a recommended act, so do not neglect it."  

سَمِعْتُ عَلِيًّا يَقُولُ «إِنَّ الْوِتْرَ لَيْسَ بِحَتْمٍ كَالصَّلَاةِ وَلَكِنَّهُ سُنَّةٌ فَلَا تَدَعُوهُ»