´It 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."
Hadith ReferenceSunan an-Nasa'i / The Book of Funerals / Hadith: 1943