Sahih Bukhari Volume 9, Book 97, Hadith 7436

حَدَّثَنَا عَمْرُو بْنُ عَوْنٍ، حَدَّثَنَا خَالِدٌ، وَهُشَيْمٌ، عَنْ إِسْمَاعِيلَ، عَنْ قَيْسٍ، عَنْ جَرِيرٍ، قَالَ كُنَّا جُلُوسًا عِنْدَ النَّبِيِّ صلى الله عليه وسلم إِذْ نَظَرَ إِلَى الْقَمَرِ لَيْلَةَ الْبَدْرِ قَالَ ‏"‏ إِنَّكُمْ سَتَرَوْنَ رَبَّكُمْ كَمَا تَرَوْنَ هَذَا الْقَمَرَ لاَ تُضَامُّونَ فِي رُؤْيَتِهِ، فَإِنِ اسْتَطَعْتُمْ أَنْ لاَ تُغْلَبُوا عَلَى صَلاَةٍ قَبْلَ طُلُوعِ الشَّمْسِ وَصَلاَةٍ قَبْلَ غُرُوبِ الشَّمْسِ، فَافْعَلُوا ‏"‏‏

Narrated By Jarir : We were sitting with the Prophet and he looked at the moon on the night of the full-moon and said, "You people will see your Lord as you see this full moon, and you will have no trouble in seeing Him, so if you can avoid missing (through sleep or business, etc.) a prayer before sunrise (Fajr) and a prayer before sunset (Asr) you must do so."