Sunan an-Nasa'i 1613
سنن النسائي#1613SahihIt was narrated from Humaid bin 'Abdur-Rahman- that is Ibn 'Awf, that Abu Hurairah said:"The Messenger of Allah (ﷺ) said: 'The best fasting after the month of Ramadan is the month of Allah, Al-Muharram, and the best prayer is prayer at night
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 Muslim
In-book reference: 20:16