حَدَّثَنَا أَسْوَدُ بْنُ عَامِرٍ وَحُسَيْنٌ قَالَا حَدَّثَنَا إِسْرَائِيلُ عَنْ أَبِي إِسْحَاقَ عَنِ الْحَارِثِ عَنْ عَلِيٍّ رَضِيَ اللَّهُ عَنْهُ قَالَ مِنْ كُلِّ اللَّيْلِ قَدْ أَوْتَرَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مِنْ أَوَّلِهِ وَأَوْسَطِهِ وَآخِرِهِ فَثَبَتَ الْوَتْرُ آخِرَ اللَّيْلِ
مسند امام احمد بن حنبل · Hadith 651
It was narrated that 'Ali (RA) said: At different times of the night the Messenger of Allah (PBUH) prayed Witr. at the beginning, in the middle and at the end. Then he settled on praying Wit r at the end of the night.
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020