Musannaf Ibn Abi Shayba 37:333

Abu Abd al-Rahman Baqi ibn Makhlad narrated to us, he said: Abu Bakr Abdullah ibn Muhammad ibn Abi Shaybah narrated to us, he said: Waki’ narrated to us, he said: al-A’mash narrated to us, from Salamah ibn Kuhayl, from Abu Zabyan, that he was with Umar. He said: He said to him, "Acquire wealth and take sheep, for it is soon that you will be prevented from the stipend."