Musnad Ahmad 25:664

'Affan narrated to us, Hammad ibn Salamah narrated to us, 'Ammar ibn Abi 'Ammar informed us, from Ibn 'Abbas, who said: "The Prophet, may Allah bless him and grant him peace, stayed in Makkah for fifteen years. For seven years, he would see the light and hear the sound, and for eight years, revelation came to him. And he stayed in Al-Madinah for ten years."