Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) said: We were digging the trench with the Prophet (peace and blessings be upon him) and carrying away the earth. He (peace and blessings be upon him) looked at us and said: "'Allahumma la 'aysha illa 'aysh al-akhirah, faghfir li al-Ansari wa al-Muhajirah' (O Allah, there is no life but the life of the Hereafter, so forgive the Ansar and the Muhajirun)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13323