He who does good in Islam will not be punished for what he did during jāhiliyyah, and he who commits evil in Islam will be punished for the previous and later deeds

The Prophet (may Allah's peace and blessings be upon him) points out the merit of entering Islam. He who embraces Islam and becomes a committed, sincere, and truthful Muslim will not be punished for the sins he committed during jāhiliyyah. In contrast, he who does wrong after entering Islam, by being a hypocrite or renouncing Islam, will be punished for what he did both during his period of disbelief and after entering Islam.