Abdullah bin Mas'ud (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Hands are three: the Hand of Allah is the uppermost, the hand of the giver is next to it, and the hand of the one who asks is the lowest until the Day of Resurrection. So refrain from asking as much as you are able. Whoever Allah has given good (blessing and abundance), it should be visible upon him. Begin with those you support, and give away the surplus wealth; you will not be blamed for (keeping) what suffices, and do not make yourself helpless."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7886