It was narrated that Anas said:

"The Messenger of Allah and Zaid bin Thabit had Sahur, then they went and started to pray Subh." We said to Anas: "How long was there between their finishing and their starting to pray?" He said: "As long as it takes a man to recite fifty Verses."

أَخْبَرَنَا أَبُو الأَشْعَثِ، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا سَعِيدٌ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، رضى الله عنه قَالَ تَسَحَّرَ رَسُولُ اللَّهِ ﷺ وَزَيْدُ بْنُ ثَابِتٍ ثُمَّ قَامَا فَدَخَلاَ فِي صَلاَةِ الصُّبْحِ . فَقُلْنَا لأَنَسٍ كَمْ كَانَ بَيْنَ فَرَاغِهِمَا وَدُخُولِهِمَا فِي الصَّلاَةِ قَالَ قَدْرَ مَا يَقْرَأُ الإِنْسَانُ خَمْسِينَ آيَةً .