Hisham bin Urwah (may Allah have mercy on him) narrates from his father that the Messenger of Allah (peace and blessings be upon him) sent a man as a collector and said: "Do not take from the people's choicest wealth; rather accept the old, the young and the defective as well."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7310