Hazrat Hasan رحمة لله علیھ once wrote the following short letter to Umar bin Abdul Azeez رحمة لله علیھ :
"Fear what Allah Ta’ala told you to fear. Take what is in your hands, and use it for what is to come. At the moment of death, sure news will come to you and peace."
Umar رحمة لله علیھ wrote back, asking Hazrat Hasan رحمة لله علیھ to advise him some more. Hazrat Hasan رحمة لله علیھ wrote back:
"Indeed the terror of the Day of Resurrection is greater than you might think. Indeed, frightful matters are near at hand. You will have to face all of that, either by facing it all and being saved, or by facing it all and being destroyed. Know that he who takes account of his own deeds will succeed, and that he who is negligent in this regard will fail. Whoever looks at the outcomes of his actions will be saved, while he who obeys his desires will be misguided. Whoever is patient and forbearing will gain profits. Whoever remains awake and vigilant regarding his deeds will be safe, whoever is safe reflects, whoever reflects sees, whoever sees understands, and whoever understands knows. Then if you slip, return and repent. And when you are remorseful, then refrain [from sins]. When you are ignorant, ask. And when you are angry, restrain your anger."