Musnad Abu Ya'la al-Mawsili 106:12

Mujahid ibn Musa narrated to us, Bahz narrated to me, Shu'bah narrated to us, 'Adi ibn Thabit narrated to me, from Al-Bara' ibn 'Azib: That the Messenger of Allah (peace be upon him) was on a journey, and he recited in the last 'Isha' prayer, in one of the two rak'ahs, "Wat-tini waz-zaytun" (By the fig and the olive).