Sahih Bukhari | Volume 1 | Hadith Number 568

Narrated by Ibn Abu Malih
I was with Buraida on a cloudy day and he said, "Offer the 'Asr prayer earlier as the Prophet said, 'Whoever leaves the 'Asr prayer will have all his (good) deeds annulled." (See Hadith No. 527 and 528)