Hadith 8:178
Ibn 'Umar (May Allah be pleased with them) reported:
The Prophet (ﷺ) said, "Salat during the night should consist of pairs of but if you fear that morning is near, then pray one Rak'ah as Witr." [Al-Bukhari and Muslim] .
وعن ابن عمر رضي الله عنهما، أن النبي صلى الله عليه وسلم ، قال: "صلاة الليل مثنى مثنى، فإذا خفت الصبح فأوتر بواحدة" ((متفق عليه))