Musannaf Ibn Abi Shayba 33:345

Jarir ibn Abd al-Hamid narrated to us, from Abd al-Aziz ibn Rufay’, from Khaythama, who said: Abdullah said: Observe people at their deathbeds. If you see a servant dying upon the best of what you see of him, then hope for good for him. And if you see him dying upon the worst of what you see of him, then fear for him. For if a servant is wretched, even if people admire some of his deeds, a devil is appointed to him who brings him down and destroys him until the wretchedness that was written for him overtakes him. And if he is happy, even if people dislike some of his deeds, an angel is appointed to him who guides him and directs him aright until the happiness that was written for him overtakes him.