Musnad Ahmad 31:80

Abu Mu'awiyah and Muhammad ibn 'Ubayd narrated to us, they said: Al-A'mash narrated to us, from Abu Salih, from Abu Sa'id, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When the people of Paradise enter Paradise and the people of the Fire enter the Fire, death will be brought as if it were a speckled ram. It will be made to stand between Paradise and the Fire, and it will be said: 'O people of Paradise, do you recognize this?' He said: They will stretch their necks and look, and they will say: 'Yes, this is death.' He said: Then it will be said: 'O people of the Fire, do you recognize this?' He said: They will stretch their necks and look, and they will say: 'Yes, this is death.' He said: Then it will be commanded to be slaughtered. He said: And it will be said: 'O people of Paradise, eternity, no death; and O people of the Fire, eternity, no death.' He said: Then the Messenger of Allah (peace and blessings of Allah be upon him) recited: {And warn them of the Day of Regret, when the matter will be decided, while they are in heedlessness} [Maryam: 39]. He said: And he gestured with his hand. Muhammad ibn 'Ubayd said in his narration: 'In heedlessness,' he said: The people of the world are in the heedlessness of the world. Muhammad ibn 'Ubayd said in his narration: 'When the people of Paradise enter Paradise, and the people of the Fire enter the Fire, death will be brought as if it were a speckled ram.'"