Musannaf Ibn Abi Shayba 17:1318

Abu Usama narrated to us, he said: Hisham narrated to us, from his father, who said: I reached Sa’d ibn ‘Ubadah while he was calling out from his fortress (uṭm): "Whoever loves fat or meat, let him come to Sa’d ibn ‘Ubadah." Then I reached his son after that, and he was calling out with it. And I was walking on the road of Medina while I was a young man, and ‘Abdullah ibn ‘Umar passed by me, heading to his land in al-‘Aliyah. He said: "O young man, come here. Look, do you see anyone on the fortress of Sa’d ibn ‘Ubadah calling out?" I looked and said: "No." He said: "You have spoken the truth."