Musannaf Ibn Abi Shayba 3:1216

Abu al-Ahwas narrated to us, from Abu Ishaq, from Amr ibn Maymun, who said: Umar led us in the Maghrib prayer. In the first rak'ah, he recited: "By the fig and the olive." In the second rak'ah, he recited: "Have you not seen how your Lord dealt with the companions of the elephant?" and "For the accustomed security of the Quraysh."