Musannaf Ibn Abi Shaybah 36597 — Accounts

It is narrated from al-Sha'bi that Sayyiduna Abu Musa (may Allah be pleased with him) wrote to Sayyiduna Umar (may Allah be pleased with him): Letters come to us and we do not know their dates, so fix a dating for us. Sayyiduna Umar (may Allah be pleased with him) consulted the Companions (may Allah be pleased with them). Some of the Companions advised that the dating be fixed from the commissioning of the Prophet (peace and blessings be upon him), and some others advised that it be fixed from the death of the Prophet (peace and blessings be upon him). Sayyiduna Umar (may Allah be pleased with him) said: I will fix the dating from the migration of the Prophet (peace and blessings be upon him), for the migration of the Prophet (peace and blessings be upon him) separated truth from falsehood. So he fixed the dating from the migration.