Musnad Ahmad 25:541

Hassan ibn Musa narrated to us, he said: Hammad ibn Salamah narrated to us, from Ammar ibn Abi Ammar, from Ibn Abbas: "That the Messenger of Allah, may Allah bless him and grant him peace, stayed in Makkah for fifteen years; eight years or seven [during which] he would see the light and hear the sound, and eight or seven [during which] it was revealed to him. And he stayed in Al-Madinah for ten [years]."