صحيح البخاري حديث رقم 575

Zaid bin Thabit said, "We took the "Suhur" (the meal taken before dawn while fasting is observed) with the Prophet (ﷺ) and then stood up for the (morning) prayer." I asked him how long the interval between the two (Suhur and prayer) was. He replied, 'The interval between the two was just sufficient to recite fifty to Sixth 'Ayat."