Sunan an-Nasa’i 449
The Book of Salah
Enjoining As-Salah And Mentioning The Differences Reported by The Narrators In The Chain Of The Hadith Of Anas Bin Malik (May Allah Be Pleased With Him), And The Different Wordings In It
Anas bin Malik and Ibn Hazm said: "The Messenger of Allah (ﷺ) said: 'Allah, the Mighty and Sublime, enjoined fifty prayers upon my Ummah, and I came back with that until I passed by Musa, peace be upon him, who said: 'What has your Lord enjoined upon your Ummah?' I said: 'He has enjoined fifty prayers on them.' Musa said to me: 'Go back to your Lord, the Mighty and Sublime, for your Ummah will not be able to do that.' So I went back to my Lord, the Mighty and Sublime, and He reduced a portion of it. Then I came back to Musa and told him, and he said: 'Go back to you Lord, for your Ummah will not be able to do that.' So I went back to my Lord, the Mighty and Sublime, and He said: 'They are five (prayers) but they are fifty (in reward), and the Word that comes from Me cannot be changed.' [1] I came back to Musa and he said: 'Go back to your Lord.' I said: 'I feel too shy before my Lord, the Mighty and Sublime.'" [1]See Surah Qaf 50:29.