The Messenger of Allah ﷺ said, "Do not press one another in asking. By Allah, none of you asks me for something and gets it from me through his persistence while I am unwilling to give it, then finds any blessing in what I gave him."
قال رسول الله ﷺ: لا تلحقوا في المسألة، فوالله لا يسألني أحد منكم شيئا فتخرج له مسألته مني شيئا وأنا له كاره فيبارك له فيما أعطيته.
Muslim narrated it in the Book of Zakat (1038) from Muhammad bin Abdullah bin Numayr, who said, Sufyan related to us, from Amr, from Wahb bin Munabbi, from his brother Hammam, from Muawiya, and he related it as mentioned.He also narrated it through another route, from Sufyan, from Amr bin Dinar, who said, Wahb bin Munabbi related to me, and I visited him at his home in Sanaa, and he fed me from a walnut tree in his house, from his brother Hammam, who said, I heard Muawiya bin Abu Sufyan say, and he related it as mentioned.Ilhaf means persistence. It is said that the beggar has practiced ilhaf in his asking when he persists, meaning he keeps clinging to the person being asked until he gives him something.