Sahih Muslim Book - 4, Hadith - 961

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ وَعَلِيُّ بْنُ حُجْرٍ وَاللَّفْظُ لِأَبِي بَكْرٍ قَالَ ابْنُ حُجْرٍ أَخْبَرَنَا وَقَالَ أَبُو بَكْرٍ حَدَّثَنَا عَلِيُّ بْنُ مُسْهِرٍ عَنْ الْمُخْتَارِ بْنِ فُلْفُلٍ عَنْ أَنَسٍ قَالَ صَلَّى بِنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ ذَاتَ يَوْمٍ فَلَمَّا قَضَى الصَّلَاةَ أَقْبَلَ عَلَيْنَا بِوَجْهِهِ فَقَالَ أَيُّهَا النَّاسُ إِنِّي إِمَامُكُمْ فَلَا تَسْبِقُونِي بِالرُّكُوعِ وَلَا بِالسُّجُودِ وَلَا بِالْقِيَامِ وَلَا بِالِانْصِرَافِ فَإِنِّي أَرَاكُمْ أَمَامِي وَمِنْ خَلْفِي ثُمَّ قَالَ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَوْ رَأَيْتُمْ مَا رَأَيْتُ لَضَحِكْتُمْ قَلِيلًا وَلَبَكَيْتُمْ كَثِيرًا قَالُوا وَمَا رَأَيْتَ يَا رَسُولَ اللَّهِ قَالَ رَأَيْتُ الْجَنَّةَ وَالنَّارَ.

It was narrated that Anas said: "The Messenger of Allah (s.a.w) led us in prayer one day, and when he had finished praying he turned to face us and said: 'O people, I am your Imam, so do not go ahead of me in bowing, prostrating, standing nor the turning, for I can see you from in front of me and behind me.' Then he said: 'By the One in Whose Hand is the soul of Muhammad! If you saw what I have seen, you would laugh little and weep much.' They said: 'What have you seen, O Messenger of Allah?' He said: 'I have seen Paradise and the Fire.'"