Sahih Bukhari Volume 1, Book 10, Hadith 860

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، قَالَ أَخْبَرَنَا سُفْيَانُ، عَنْ عَمْرٍو، قَالَ أَخْبَرَنِي كُرَيْبٌ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ بِتُّ عِنْدَ خَالَتِي مَيْمُونَةَ لَيْلَةً، فَنَامَ النَّبِيُّ صلى الله عليه وسلم فَلَمَّا كَانَ فِي بَعْضِ اللَّيْلِ قَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَتَوَضَّأَ مِنْ شَنٍّ مُعَلَّقٍ وُضُوءًا خَفِيفًا ـ يُخَفِّفُهُ عَمْرٌو وَيُقَلِّلُهُ جِدًّا ـ ثُمَّ قَامَ يُصَلِّي، فَقُمْتُ فَتَوَضَّأْتُ نَحْوًا مِمَّا تَوَضَّأَ، ثُمَّ جِئْتُ فَقُمْتُ عَنْ يَسَارِهِ، فَحَوَّلَنِي فَجَعَلَنِي عَنْ يَمِينِهِ، ثُمَّ صَلَّى مَا شَاءَ اللَّهُ، ثُمَّ اضْطَجَعَ فَنَامَ حَتَّى نَفَخَ، فَأَتَاهُ الْمُنَادِي يُؤْذِنُهُ بِالصَّلاَةِ فَقَامَ مَعَهُ إِلَى الصَّلاَةِ، فَصَلَّى وَلَمْ يَتَوَضَّأْ‏.‏ قُلْنَا لِعَمْرٍو إِنَّ نَاسًا يَقُولُونَ إِنَّ النَّبِيَّ صلى الله عليه وسلم تَنَامُ عَيْنُهُ وَلاَ يَنَامُ قَلْبُهُ‏.‏ قَالَ عَمْرٌو سَمِعْتُ عُبَيْدَ بْنَ عُمَيْرٍ يَقُولُ إِنَّ رُؤْيَا الأَنْبِيَاءِ وَحْىٌ ثُمَّ قَرَأَ ‏{‏إِنِّي أَرَى فِي الْمَنَامِ أَنِّي أَذْبَحُكَ‏}

Narrated By Ibn 'Abbas : One night I slept at the house of my aunt Maimuna and the Prophet slept (too). He got up (for prayer) in the last hours of the night and performed a light ablution from a hanging leather skin. ('Amr, the sub-narrator described that the ablution was very light). Then he stood up for prayer and I got up too and performed the ablution in the same way and joined him on his left side. He pulled me to the right and prayed as much as Allah will. Then he lay down and slept and I heard his breath sounds till the Mu'adh-dhin came to him to inform him about the (Fajr) prayer. He left with him for the prayer and prayed without repeating the ablution. (Sufyan the sub-narrator said: We said to 'Amr, "Some people say, 'The eyes of the Prophet sleep but his heart never sleeps.' " 'Amr said, "'Ubai bin 'Umar said, 'The dreams of the Prophets are Divine Inspirations. Then he recited, '(O my son), I have seen in dream that I was slaughtering you (offering you in sacrifice).") (37.102)