Sahih Bukhari
Merits of the Helpers in Madinah (Ansaar)
Volume: 005 / Book Number: 058 / Hadith Number: 190
Narrated Ibn 'Abbas:
Allah's Apostle was inspired Divinely at the age of forty. Then he stayed in Mecca for thirteen years, and then was ordered to migrate, and he migrated to Medina and stayed there for ten years and then died.