Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "There is no faith for one who has no trustworthiness, and one who transgresses in collecting zakah is like one who withholds it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7281