Musnad Ahmad 658:61

Abu Khalid al-Ahmar narrated to us, Yahya ibn Sa'id narrated to us, from 'Adi ibn Thabit, from al-Bara' ibn 'Azib, who said: "I prayed the Maghrib prayer behind the Prophet, may Allah bless him and grant him peace, and he recited 'At-Tin wa az-Zaytun' (The Fig and the Olive)."