Sahih al-Bukhari 993
Book 14: Witr Prayer · Narrated by `Abdullah bin `Umar
Arabic
حَدَّثَنَا يَحْيَى بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنِي ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي عَمْرٌو، أَنَّ عَبْدَ الرَّحْمَنِ بْنَ الْقَاسِمِ، حَدَّثَهُ عَنْ أَبِيهِ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم " صَلاَةُ اللَّيْلِ مَثْنَى مَثْنَى، فَإِذَا أَرَدْتَ أَنْ تَنْصَرِفَ فَارْكَعْ رَكْعَةً تُوتِرُ لَكَ مَا صَلَّيْتَ ". قَالَ الْقَاسِمُ وَرَأَيْنَا أُنَاسًا مُنْذُ أَدْرَكْنَا يُوتِرُونَ بِثَلاَثٍ، وَإِنَّ كُلاًّ لَوَاسِعٌ أَرْجُو أَنْ لاَ يَكُونَ بِشَىْءٍ مِنْهُ بَأْسٌ.
English translation
Narrated `Abdullah bin `Umar:The Prophet (ﷺ) said, "Night prayer is offered as two rak`at followed by two rak`at and so on, and if you want to finish it, pray only one rak`a which will be witr for all the previous rak`at." Al-Qasim said, "Since we attained the age of puberty we have seen some people offering a three-rak`at prayer as witr and all that is permissible. I hope there will be no harm in it
Reference: Sahih al-Bukhari 993, Book of Witr Prayer. English translation by Dr. Muhammad Muhsin Khan.