(34) باب حَفْرِ الْخَنْدَقِ
Narrated Anas:
The Emigrants and the Ansar started digging the trench around Medina carrying the earth on their backs and saying, "We are those who have given a pledge of allegiance to Muhammad that we will I carry on Jihad as long as we live." The Prophet (ﷺ) kept on replying, "O Allah, there is no good except the good of the Hereafter; so confer Your Blessings on the Ansar and the Emigrants."
Reference: Sahih al-Bukhari 2835
In-book reference: Book 56, Hadith 51
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 88