Sunan an-Nasa'i 5026
سنن النسائي#5026SahihIt was narrated from Abu Hurairah that:The Prophet [SAW] said: "Whoever stands (in the voluntary night prayer of) Ramadan out of faith and in the hope of reward, his previous sins will be forgiven
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 ZaiHasan
In-book reference: 47:42