سُنَنُ النَّسَائِيِّ
Sunan an-Nasa’i 1667
The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
How to pray at night
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.'"
Sunan an-Nasa'i, 1667Sahih (Darussalam)