حَدَّثَنَا سُفْيَانُ عَنِ الزُّهْرِيِّ عَنْ سَالِمٍ عَنْ أَبِيهِ قَالَ سَمِعْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سُئِلَ كَيْفَ يُصَلَّى بِاللَّيْلِ قَالَ لِيُصَلِّ أَحَدُكُمْ مَثْنَى مَثْنَى فَإِذَا خَشِيَ الصُّبْحَ فَلْيُوتِرْ بِوَاحِدَةٍ
مسند امام احمد بن حنبل · Hadith 4559
It was narrated from Saalim that his father said: I heard the Prophet (PBUH) being asked: How are the night prayers to be performed? He said: "Let one of you pray two (rak'ahs) by two. then when he fears that dawn is about to break, let him pray one rah'ah as Witr.”
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020