551. Narrated Aboo Huraira (radhi Allaahu anhu) : Allah’s Messenger (Sallallaahu Alaihi Wasallam) said,
“Whoever attends a funeral procession till he offers the funeral prayer for it, will get a reward equal to one Qiraat, and whoever accompanies it till burial, will get a reward equal to two Qiraat?” He replied, “Like two huge mountains.”
[Saheeh Al-Bukhaari, Hadeeth No. 410, Vol. 2]
Source : The Book Of Funerals (al-Janaaiz) : Chapter 17 – The superiority of the feneral prayer and of following the funeral. procession. Al-Lulu Wal-Marjan,Compiled by : Fuwad Abdul-Baqi,Translated by : Dr. Muhammad Muhsin Khan