Sahih Muslim 318
صحيح مسلم#318SahihIt is narrated on the authority of Abdullah b. Mas'ud that some people said to the Messenger of Allah (ﷺ):Messenger of Allah, would we be held responsible for our deeds committed in the state of ignorance (before embracing Islam)? Upon his he (the Holy Prophet) remarked: He who amongst you performed good deeds in Islam, He would not be held responsible for them (misdeeds which he committed in ignorance) and he who committed evil (even after embracing Islam) would be held responsible or his misdeeds that he committed in the state of ignorance as well as in that of Islam
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 1:225