Sahih Muslim 1840
صحيح مسلم#1840SahihThis hadith has been narrated by Ibn 'Umar from the Messenger of Allah (ﷺ), but in the hadith transmited by Musa b. 'Uqba, this addition is made:" When one who had committed the Qur'an to memory (or who is familiar with it) gets up (for night prayer) and recites it night and day, it remains fresh in his mind, but if he does not get up (for prayer and thus does not recite it) he forgets it
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 6:268