Sunan an-Nasa'i 5032
سنن النسائي#5032SahihIt was narrated from Abu Hurairah that:The Prophet [SAW] said: "Whoever follows the funeral procession of a Muslim out of faith and in the hope of reward, then offers the funeral prayer for him and waits until he is placed in his grave, then he will have two Qirats, each of which is like Mount Uhud. Whoever offers the funeral prayer for him then returns, he will have one Qirat
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: 47:48