The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
20/26. Chapter:
How to pray at night
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ قُدَامَةَ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ حَبِيبٍ، عَنْ طَاوُسٍ، قَالَ قَالَ ابْنُ عُمَرَ سَأَلَ رَجُلٌ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنْ صَلاَةِ اللَّيْلِ فَقَالَ " مَثْنَى مَثْنَى فَإِذَا خَشِيتَ الصُّبْحَ فَوَاحِدَةٌ " .
It was narrated that Tawus said: "Ibn Umar said: "A man asked the Messenger of Allah (ﷺ) about prayer at night. He said: "Two by two, and if you fear that dawn will come, then one.'"
Reference : Sunan an-Nasa'i 1667In-book reference : Book 20, Hadith 70English translation : Vol. 2, Book 20, Hadith 1668