Sunan an-Nasa'i · Hadith 1671
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " صَلاَةُ اللَّيْلِ مَثْنَى مَثْنَى فَإِذَا خِفْتَ الصُّبْحَ فَأَوْتِرْ بِوَاحِدَةٍ " .
It was narrated from Ibn Umar that:The Prophet (ﷺ) said: "prayers at night are (offered) two by two, then if you fear that dawn will come, pray witr with one
Sahih · Abu GhuddahSahih · Al-AlbaniSahih - Agreed Upon · Zubair Ali Zai