Hazrat Qais bin Sa’d (may Allah have mercy on him) narrates that Hazrat Ata (may Allah have mercy on him) used to say: If any man from among the Muslims kills another man and then adopts disbelief and joins the polytheists and stays among them, then later he repents and returns, his repentance from polytheism will be accepted, and the punishment of retribution (qisas) will be enforced upon him. And if someone joins the polytheists in such a state that he has not committed murder, but only adopted disbelief, then fought against the Muslims and martyred some Muslims, then he repents and returns, his repentance will be accepted and nothing will be obligatory upon him.