The Messenger of Allah ﷺ said, "Injustice will be darknesses on the Day of Resurrection."
قال رسول الله ﷺ: إن الظلم ظلمات يوم القيامة.
Bukhari reported it in the Book of Injustices (2447), and Muslim in the Book of Righteousness and Kinship (2579: 57), both through the route of Abdul-Aziz Majishun, from Abdullah bin Dinar, from Ibn Umar, who narrated it.