The Book of Faith (Kitab Al-Iman)
Muslim :: Book 1 : Hadith 223
Hakim b. Hizam reported to 'Urwa b. Zubair that he said to the Messenger of Allah (may peace be upon him): Messenger of Allah, do you think if there is any reward (of the Lord with me on the Day of Resurrection) for the deeds of religious purification that I performed in the state of ignorance, such as charity, freeing a slave, cementing of blood-relations? Upon this he (the Apostle of Allah) said to him: You have accepted Islam with all the previous virtues that you had practised.