(55) باب بَيَانِ حُكْمِ عَمَلِ الْكَافِرِ إِذَا أَسْلَمَ بَعْدَهُ
Hakim b. Hizam reported to 'Urwa b. Zubair that he said to the Messenger of Allah (ﷺ):
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 Messenger of Allah) said to him: You have accepted Islam with all the previous virtues that you had practised.
Reference: Sahih Muslim 123 b
In-book reference: Book 1, Hadith 231
USC-MSA web (English) reference(deprecated numbering scheme): Book 1, Hadith 223