Nafi' narrates from Sayyiduna Ibn Umar (may Allah be pleased with them both) that he said: Pay the zakah of your wealth to those who have been placed in authority over your affairs; whoever does good, it is for himself, and whoever sins, its burden is upon him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7381