Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) sent Sayyiduna Umar (may Allah be pleased with him) to collect zakah.
Sayyiduna Abu Humayd al-Sa'idi (may Allah be pleased with him) said: He (peace and blessings be upon him) appointed a man called Ibn al-Lutbiyyah as collector over the zakah of Banu Sulaym. When he came back, he took account from him. There are other hadiths on this as well.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7358