It is narrated that ‘Uthmân b. Áffân – Allâh be pleased with him – said in a sermon
Son of Adam! Know that the angel of death who has been assigned to you has not ceased to pass you and move on to others, ever since you have been in this world. But it is as if he is about to pass someone else and move on to target you, so be careful and prepare for him (by correcting your deeds). And do not forget him, for he does not forget you. And know o son of Adam, if you are heedless about yourself and do not prepare, no one else will prepare for you. You must meet Allah the Mighty and Majestic, so take for yourself and do not leave it to someone else. Peace be on you
Abû Bakr Al-Daynûrî, Al-Mujâlasah wa Jawâhir Al-Ílm 2: 73, 74