Muhammad Ibn Zaid Shakham narrates: One night I was a guest of Imam Ja’far as-Sadiq (a.s). In the morning he asked, “What provisions of journey do you have?” I told him what I had. He said, “May be it would be insufficient.” After that he gave me two gold coins and twenty dirhams. I took them and went away. But, by chance I could not commence my journey that day. The Imam (a.s) learnt that I was still in town. He sent for me and asked, “Why did you not come back to me? Be my guest, till the time you stay in Medina. And if you need anything just mention it.” I said that I was very fond of milk. At once, the Imam gave me a milk-giving she goat and then he taught me a supplication and told me to recite it in the month of Rajab.
The Imam used to serve his guests with the best foods, and himself ate bread and vinegar. He used to say, “This is the diet of the prophets and we also eat this only.”
Reference :Akhlaq al-A’imma, Morals & Manners of the Holy Imams