Hadith 179

Riyad as-Salihin

Book 8: The Book of Virtues

Chapter 212

Excellence of Standing in Prayer at Night

باب فضل قيام الليل‏:‏

Riyad as-Salihin 1169
وعنه قال‏:‏ كان النبي صلى الله عليه وسلم ، يصلي من الليل مثنى مثنى، ويوتر بركعة‏.‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏ ‏.‏
Ibn 'Umar (May Allah be pleased with them) reported:

The Prophet (ﷺ) performed the night prayer in pairs (i.e., Rak'ah) and made it odd number by observing one Rak'ah (as Witr).[Al-Bukhari and Muslim].