Musannaf Ibn Abi Shayba 33:448

Waki’ narrated to us, from Mis’ar, from ‘Amr ibn Murrah, from Abu al-Bakhtari, who said: A man from Banu ‘Abs accompanied Salman. He came to the Tigris and Salman said to him, "Drink." So he drank. Then he said to him, "Drink." So he drank. Then he said to him, "Drink." So he drank. Then he said to him, "O brother of Banu ‘Abs, do you see this drink of yours having diminished anything from the water of the Tigris? Likewise, knowledge does not run out, so seek from knowledge that which benefits you." Then he passed by Nahrawan, and there were foods and heaps of grain being winnowed. He said, "O brother of Banu ‘Abs, indeed He who opened this for you, granted it to you, and provided it to you, was capable of its treasures while Muhammad, peace and blessings of Allah be upon him, was alive, and they would enter the evening and the morning while there was not a *qafiz* of wheat among them." Then he mentioned Jalula and what Allah opened for the Muslims therein. He said, "O brother of Banu ‘Abs, indeed Allah gave you this and granted it to you, and He was capable of it while Muhammad was alive."