Musnad Ahmad 25:987

Abu Kamil narrated to us, Hammad 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 the radiance and hear the voice, and for eight years, revelation was sent down to him. And he stayed in Al-Madinah for ten [years]."