Abu Huraira (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings of Allah be upon him) said: (On the Day of Resurrection) Allah will smile at two men, one of whom killed the other, yet both will enter Paradise. The first fought in the way of Allah and was martyred, then Allah granted the killer the ability to repent (i.e., the killer became a Muslim), and he too was martyred in the way of Allah. (Thus, in the end, both the killer and the killed entered Paradise.)