حَدَّثَنَا عَبْدُ الْأَعْلَى بْنُ عَبْدِ الْأَعْلَى عَنْ خَالِدٍ عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ عَنِ ابْنِ عُمَرَ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ صَلَاةُ اللَّيْلِ مَثْنَى مَثْنَى فَإِذَا خَشِيتَ الْفَجْرَ فَأَوْتِرْ بِوَاحِدَةٍ
مسند امام احمد بن حنبل · Hadith 4987
It was narrated from Ibn Umar that the Prophet (PBUH) said: "The night prayers are two by two, then if you fear that dawn is approaching, pray Witr with rak'ah."
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020