A man from Banu Asad says: My wife and I stopped at Baqi' al-Gharqad. My wife said to me: Go to the Prophet (peace and blessings be upon him) and ask him for something to bring back (so that) we may eat. I went to the Prophet (peace and blessings be upon him). I saw a man who was asking, and the Prophet (peace and blessings be upon him) was saying: "I have nothing to give you." When the man went away he was angry, and he was saying: "By Allah! You give to whomever you wish." The Prophet (peace and blessings be upon him) said: "He is angry, and I have nothing to give him." Then he (peace and blessings be upon him) said: "Whoever asks while he has an uqiyah or something equal to it has asked importunately." Al-Asadi says: I said (to myself): Our milch camel is better than an uqiyah, and an uqiyah is forty dirhams. He said: So I went back and did not ask him for anything. After that barley and raisins were brought to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) gave us a share of it, until Allah Almighty made us free of need.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13209