Sunan an-Nasai Book 20, Hadith 1606

أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا زَيْدُ بْنُ الْحُبَابِ، قَالَ أَخْبَرَنِي مُعَاوِيَةُ بْنُ صَالِحٍ، قَالَ حَدَّثَنِي نُعَيْمُ بْنُ زِيَادٍ أَبُو طَلْحَةَ، قَالَ سَمِعْتُ النُّعْمَانَ بْنَ بَشِيرٍ، عَلَى مِنْبَرِ حِمْصَ يَقُولُ قُمْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي شَهْرِ رَمَضَانَ لَيْلَةَ ثَلاَثٍ وَعِشْرِينَ إِلَى ثُلُثِ اللَّيْلِ الأَوَّلِ ثُمَّ قُمْنَا مَعَهُ لَيْلَةَ خَمْسٍ وَعِشْرِينَ إِلَى نِصْفِ اللَّيْلِ ثُمَّ قُمْنَا مَعَهُ لَيْلَةَ سَبْعٍ وَعِشْرِينَ حَتَّى ظَنَنَّا أَنْ لاَ نُدْرِكَ الْفَلاَحَ وَكَانُوا يُسَمُّونَهُ السُّحُورَ ‏.‏

Nu'aim bin Ziyad Abu Talhah said:"I heard An-Nu'man bin Bashir on the minbar in Hims saying: "We prayed Qiyam with the Messenger of Allah (ﷺ) during Ramadan on the night of the twenty-third until one-third of the night had passed, then we prayed Qiyam with him on the night of the twenty-fifth until one-half of the night had passed, then we prayed Qiyam with him on the night of the twenty-seventh until we thought that we would miss Al-Falah- that is what they used to call suhur