Sahih Bukhari Volume 5, Book 59, Hadith Number 424.

Narrated By Sahl bin Sad : We were with Allah’s Apostle in the Trench, and some were digging the trench while we were carrying the earth on our shoulders. Allah’s Apostle said, ‘O Allah! There is no life except the life of the Hereafter, so please forgive the Emigrants and the Ansar.”