Narrated by Abu Huraira
Allah's Apostle said, "(A believer) who accompanies the
funeral procession of a Muslim out of sincere faith and
hoping to attain Allah's reward and remains with it till the
funeral prayer is offered and the burial ceremonies are
over, he will return with a reward of two Qirats. Each
Qirat is like the size of the (Mount) Uhud. He who offers
the funeral prayer only and returns before the burial, will
return with the reward of one Qirat only."

Volume 1, Book 2, Number 45 : sahih bukhari

like .