The trials are presented to the hearts, like a reed mat, stick by stick

The Commander of the Believers, ‘Umar ibn al-Khattāb (may Allah be pleased with him), was in his assembly, and with him was a group of the Companions (may Allah be pleased with them), so he said to them: Who among you heard the Messenger of Allah (may Allah's peace and blessings be upon him) mention the trials? Some people said: We heard him mention the trials. ‘Umar (may Allah be pleased with him) said: Perhaps you mean the trial and test a man faces within his household: with his wife and children, due to his excessive love for them, his miserliness towards them, his being preoccupied with them to the detriment of much goodness, or his negligence in fulfilling their rights, disciplining them, and educating them. Likewise, the trial of a man with his neighbor and similar matters—perhaps this is what you mean? They said: Yes. He said: Those are trials that require accountability, and among them are sins that can be hoped to be expiated by good deeds, such as prayer, fasting, and charity. But who of you heard the Prophet (may Allah's peace and blessings be upon him) mention the public trials due to their great severity and extensive prevalence, shaking people like the waves of the sea in turmoil? The people kept silent, and Hudhayfah ibn al-Yamān (may Allah be pleased with him and his father) said: I heard him. ‘Umar (may Allah be pleased with him) rejoiced and said to him: May Allah bless your father for bringing someone like you; speak. Hudhayfah said: He (may Allah's peace and blessings be upon him) said: Trials appear and cling to the surface and sides of a person's heart, just as the straw mat clings to the side of one lying on it. The heart is deeply impacted by how tightly the trials adhere to it. These trials are repeated and recur, one after another. Any heart they enter, that embraces them and allows them to mix within it, as a drink permeates a body, becomes marked with a black spot. And any heart that rejects them is marked with a white spot until hearts become of two kinds: a white heart, firm in its bond of faith, free from defects, and unaffected by trials, like a smooth, polished rock upon which nothing sticks—such a heart is unharmed by any trial until it meets Allah. The other heart is a heart that has turned black from the trials, like a tilted or overturned pitcher that cannot hold water. Similarly, this heart does not retain any good or wisdom. It does not acknowledge what is right, nor does it denounce what is evil, except for what it desires and craves. Hudhayfah said to ‘Umar: These trials will not emerge during your lifetime, and between you and them is a closed door that is about to be broken. ‘Umar asked: Will it be broken completely? If it were opened, perhaps it would have been restored. Hudhayfah replied: No, it will be broken. And that door is a man who will be killed or die. What I have mentioned is a true and confirmed report, not from the scriptures of the People of the Book, nor from the opinion of any scholar, but from the Hadīth of the Prophet (may Allah's peace and blessings be upon him).