Sunan an-Nasa'i 1941
سنن النسائي#1941SahihIt was narrated that 'Abdullah bin Al-Mughaffal said:"The Messenger of Allah said: 'Whoever follows a Janazah until it is finished, he will have two Qirats, and whoever goes back before it is finished, 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 ZaiSahih
In-book reference: 21:124