Musnad Abu Ya'la al-Mawsili 42:354

Zuhayr narrated to us, Jarir narrated to us, from al-A’mash, from ‘Atiyyah, from Abu Sa’id al-Khudri, who said: Two men entered upon the Messenger of Allah (may Allah bless him and grant him peace) and asked him for the price of a camel. He assisted them with two dinars. They went out from his presence, and Umar met them. They spoke and praised what was good, and thanked what the Messenger of Allah (may Allah bless him and grant him peace) had done for them. Umar entered upon the Prophet (may Allah bless him and grant him peace) and informed him of what they had said. The Prophet (may Allah bless him and grant him peace) said: "But so-and-so, I gave him between ten and one hundred, yet he did not say that. Indeed, one of them asks me, then he departs with his request tucked under his arm, and it is nothing but fire." Umar said: "You give us what is fire?" He said: "They refuse except to ask me, and Allah refuses for me to be stingy."