Musnad Ahmad 658:236

Waki’ narrated to us, from Mis’ar, and Muhammad ibn ‘Ubayd narrated to us, from Mis’ar, from ‘Adi ibn Thabit, from al-Bara’ who said: "I heard the Prophet, peace and blessings of Allah be upon him, reciting during the Isha prayer." Muhammad said: "The latter [part of the prayer] with 'At-Tin wa az-Zaytun' (The Fig and the Olive)."