Sunan an-Nasa'i 459
سنن النسائي#459SahihIt was narrated that Anas said:"A man asked the Messenger of Allah (ﷺ): 'O Messenger of Allah, how many prayers has Allah enjoined upon His slaves?' He said: 'Allah has enjoined upon His slaves (five) prayers.' He said: 'O Messenger of Allah, is there anything before them or after them?' He said: 'Allah has enjoined upon His salves (five) prayers.' The man swore that he would not do anything more or less than that. The Messenger of Allah (ﷺ) said: 'If he is speaking the truth he will most certainly enter Paradise
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 5:12