Abu al-Malih al-Hudhali narrates from his father (may Allah be pleased with him), who said: One day I was with the Messenger of Allah (peace and blessings be upon him) in a house, and he (peace and blessings be upon him) said: "Allah Almighty does not accept prayer without purification, nor does He accept charity from wealth gained through treachery."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 188