Abu Dawud Book 15, Hadith Number 3313.

Narated By Ka’b ibn Malik : Ka’b ibn Malik said to AbuLubabah; or someone else whom Allah wished; or to the Prophet (PBUH): To make my repentance complete I should depart from the house of my people in which I fell into sin, and that I should divest myself of all my property as sadaqah (alms). He said: A third (of your property) will be sufficient for you.