Sunan an-Nasa'i, Volume 3, Book 22, Hadith 2157 (DarusSalam) ⓘ

Hisam reported from Qatadah, from Anas, that Zaid bin Thabir said; "We took Sahur with the Messenger of Allah then we went to pray." I said: "How long was there between them?" He said: "As long as it takes a man to recite fifty verses."

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا وَكِيعٌ، قَالَ حَدَّثَنَا هِشَامٌ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، عَنْ زَيْدِ بْنِ ثَابِتٍ، قَالَ تَسَحَّرْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم ثُمَّ قُمْنَا إِلَى الصَّلاَةِ ‏.‏ قُلْتُ كَمْ كَانَ بَيْنَهُمَا قَالَ قَدْرَ مَا يَقْرَأُ الرَّجُلُ خَمْسِينَ آيَةً ‏.‏