Musannaf Ibn Abi Shayba 28:389

Abu Mu'awiyah narrated to us, from 'Asim, from Abu 'Uthman, who said: When 'Utbah arrived in Azerbaijan, he was served *khabis* (a sweet dish). He tasted it and found it sweet, so he said, "If you were to make some of this for the Commander of the Faithful!" He said: So two large containers were made for him, then he loaded them onto a camel with two men and sent them to him. When they arrived before 'Umar, he said, "What is this?" They said, "This is *khabis*." He tasted it, and it was sweet. He said, "Do all the Muslims eat their fill of this in their homes?" They said, "No." He said, "Then return them both." Then he wrote to him: "To proceed: It is not from your toil, nor from the toil of your father, nor from the toil of your mother. Feed the Muslims from what you feed yourself in your home."