Musannaf Ibn Abi Shayba 33:939

Abu Usama narrated to us, from Awf, from Abu Qahdham, who said: Ibn Ziyad was brought a pouch containing grains of wheat the size of date pits, which were found in one of the houses of the Chosroes. Written with them was: "This grew in a time when people used to act in it with obedience to Allah."