حَدَّثَنَا حَرْمَلَةُ بْنُ يَحْيَى الْمِصْرِيُّ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ بْنُ يَزِيدَ، عَنِ ابْنِ شِهَابٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏"‏ فَرَضَ اللَّهُ عَلَى أُمَّتِي خَمْسِينَ صَلاَةً فَرَجَعْتُ بِذَلِكَ ‏.‏ حَتَّى آتِيَ عَلَى مُوسَى فَقَالَ مُوسَى مَاذَا افْتَرَضَ رَبُّكَ عَلَى أُمَّتِكَ قُلْتُ فَرَضَ عَلَىَّ خَمْسِينَ صَلاَةً ‏.‏ قَالَ فَارْجِعْ إِلَى رَبِّكَ فَإِنَّ أُمَّتَكَ لاَ تُطِيقُ ذَلِكَ ‏.‏ فَرَاجَعْتُ رَبِّي فَوَضَعَ عَنِّي شَطْرَهَا فَرَجَعْتُ إِلَى مُوسَى فَأَخْبَرْتُهُ فَقَالَ ارْجِعْ إِلَى رَبِّكَ فَإِنَّ أُمَّتَكَ لاَ تُطِيقُ ذَلِكَ ‏.‏ فَرَاجَعْتُ رَبِّي فَقَالَ هِيَ خَمْسٌ وَهِيَ خَمْسُونَ لاَ يُبَدَّلُ الْقَوْلُ لَدَىَّ ‏.‏ فَرَجَعْتُ إِلَى مُوسَى فَقَالَ ارْجِعْ إِلَى رَبِّكَ ‏.‏ فَقُلْتُ قَدِ اسْتَحْيَيْتُ مِنْ رَبِّي ‏"‏ ‏.‏

It wasnarrated that Anas bin Malik said: “The Messenger of Allah (PBUH)said: ‘Allah enjoined fifty prayers upon my nation, and I came backwith that until I came to Musa. Musa said: ‘What has your Lordenjoined upon your nation?’ I said: ‘He has enjoined fiftyprayers on me.’ He said: ‘Go back to your Lord, for your nationwill not be able to do that.’ So I went back to my Lord, and Hereduced it by half. I went back to Musa and told him, and he said:‘Go back to your Lord, for your nation will not be able to dothat.’ So I went back to my Lord, and He said: ‘They are five andthey are fifty; My Word does not change.’ So I went back to Musaand he said: ‘Go back to your Lord.’ I said: ‘I feel shy beforemy Lord.’” Translation Not Available

Book Ref: Sunan Ibn Majah Book 5 Hadith 1399
Web Ref:  Sunan Ibn Majah Vol 1 Book 5 Hadith 1399