Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Khaythamah that he says Hazrat Abdullah said: Observe people near their sleeping places. So when you see a servant dying in the best state, then have hope of good for him, and when you see a servant dying in the worst state, then fear for him. Because when he is wretched... even if some of his deeds amaze people... then a devil is appointed for him who leads him astray and destroys him until that wretchedness overtakes him which is destined for him. And when a servant is fortunate... even if some of his deeds are disliked by people... then an angel is appointed for him who guides him and sets him on the right path until the destined happiness overtakes him.