Sahih Bukhari Volume 002, Book 023, Hadith Number 409.

Narated By Nafi : Ibn Umar was told that Abu Huraira said, "Whoever accompanies the funeral procession will have a reward equal to one Qirat." Ibn 'Umar said, "Abu Huraira talks of a too enormous reward." 'Aisha attested Abu Huraira's narration and said, "I heard Allah's Apostle saying like that." Ibn Umar said, "We have lost numerous Qirats."