A man from among the people of the desert asked the Messenger of Allah ﷺ about prayer at night. He said:"(It is) two by two, and Witr is one rak'ah at the end of the night."  

أَنَّ رَجُلاً مِنْ أَهْلِ الْبَادِيَةِ سَأَلَ رَسُولَ اللَّهِ ﷺ عَنْ صَلاَةِ اللَّيْلِ قَالَ مَثْنَى مَثْنَى وَالْوَتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ  

“The Messenger of Allah ﷺ used to pray (voluntary prayers) at night two by two, and he would pray one Rak’ah of Witr.”  

كَانَ رَسُولُ اللَّهِ ﷺ يُصَلِّي مِنَ اللَّيْلِ مَثْنَى مَثْنَى وَيُوتِرُ بِرَكْعَةٍ  

[Machine] The Messenger of Allah ﷺ used to pray the night prayer in pairs, then he would perform Witr prayer with one rak'ah at the end of the night. After that, he would stand up as if hearing the Adhan or the Iqamah in his ears.  

كَانَ رَسُولُ اللهِ ﷺ يُصَلِّي اللَّيْلَ مَثْنَى مَثْنَى ثُمَّ يُوتِرُ بِرَكْعَةٍ مِنْ آخِرِ اللَّيْلِ ثُمَّ يَقُومُ كَأَنَّ الْأَذَانَ أَوِ الْإِقَامَةَ فِي أُذُنَيْهِ  

The Prophet ﷺ said: "Witr is one rak'ah at the end of the night." (Using translation from Nasāʾī 1689)   

عَنِ النَّبِيِّ ﷺ قَالَ صَلَاةُ اللَّيْلِ مَثْنَى مَثْنَى وَالْوِتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ  

[Machine] The Messenger of Allah ﷺ said, "The night prayer should be performed in pairs of two, and the Witr prayer should be a single unit of prayer at the end of the night."  

عَنْ رَسُولِ اللهِ ﷺ قَالَ «صَلَاةُ اللَّيْلِ مَثْنَى مَثْنَى وَالْوِتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ»  

A man who lived in the desert asked the Messenger of Allah ﷺ about the prayer at night. He made a sign with his two fingers-in this way in pairs. The witr consists of one rak'ah towards the end in night. (Using translation from Abū Dāʾūd 1421)   

أَنَّ رَجُلًا سَأَلَ رَسُولَ اللهِ ﷺ عَنْ صَلَاةِ اللَّيْلِ فَقَالَ «مَثْنَى مَثْنَى وَالْوَتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ»  

"صَلاَةُ اللَّيلِ مَثْنَىَ مثنى، وَالْوِترُ ركعةٌ مِنْ آخِرِ اللَّيْلِ".