Sahih al-Bukhari 1921
Sahih al-Bukhari · Book 30: Fasting · Interval between the Sahur and Salat-ul-Fajr
Narrated Anas:
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ ، حَدَّثَنَا هِشَامٌ ، حَدَّثَنَا قَتَادَةُ ، عَنْ أَنَسٍ ، عَنْ زَيْدِ بْنِ ثَابِتٍ ـ رضى الله عنه ـ قَالَ تَسَحَّرْنَا مَعَ النَّبِيِّ صلى الله عليه وسلم ثُمَّ قَامَ إِلَى الصَّلاَةِ. قُلْتُ كَمْ كَانَ بَيْنَ الأَذَانِ وَالسَّحُورِ قَالَ قَدْرُ خَمْسِينَ آيَةً.
Zaid bin Thabit said, "We took the Suhur with the Prophet (ﷺ) . Then he stood for the prayer." I asked, "What was the interval between the Suhur and the Adhan?" He replied, "The interval was sufficient to recite fifty verses of the Qur'an."