Ibn Ka'b bin Malik (may Allah have mercy on him) narrates from his father (Sayyiduna Ka'b bin Malik, may Allah be pleased with him) that he, or Abu Lubabah (may Allah be pleased with him), or whomever Allah willed, said to the Prophet (peace and blessings be upon him): "Part of my repentance is that I leave the house of my people in which I committed the sin, and that I part with all my property as charity." He (peace and blessings be upon him) said: "Give only a third of your wealth in charity; that will suffice for you."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 20051