It was narrated from Ibn 'Abbas (رضي الله عنه) that a man came to him and said:

What do you think of a man who kills another man deliberately? He said: “his recompense is Hell to abide therein; and the Wrath and the Curse of Allah are upon him, and a great punishment is prepared for him” [an-Nisa' 4:93]. He said: It was one of the last verses to be revealed, and nothing abrogated it, until the Messenger of Allah (ﷺ) died, and no revelation came down after the Messenger of Allah (ﷺ) died. He said: What do you think if he repents, believes and does righteous deeds, then follows true guidance? He said: How can his repentance be accepted, when I heard the Messenger of Allah (ﷺ) say, “May his mother be berest of him! If a man kills another man deliberately, he [the victim] will come on the Day of Resurrection holding on to his killer with his right or left hand, or holding on to his killer's head with his right or left hand, and with his vein gushing with blood before the Throne, saying: O Lord, ask Your slave why he killed me.”