Injustice will be excessive darkness on the Day of Judgment
Sahih/Authentic with its two versionsعن ابن عمر رضي الله عنهما مرفوعا: «الظلم ظلمات يوم القيامة». عن جابر رضي الله عنهما مرفوعا: «اتقوا الظلم، فإن الظلم ظلمات يوم القيامة، واتقوا الشُّحَ؛ فإنه أَهْلَكَ من كان قبلكم».
Ibn ‘Umar (may Allah be pleased with him) reported: The Prophet (may Allah's peace and blessings be upon him) said: ‘Injustice will be excessive darkness on the Day of Judgment.’" Jābir (may Allah be pleased with him) reported: “The Prophet (may Allah's peace and blessings be upon him) said: ‘Fear injustice, for indeed, injustice will be excessive darkness on the Day of Judgment. And fear miserliness, for it destroyed those who were before you.'"
Explanation
Both of these Hadīths are proofs of the impermissibility of injustice. The injustice mentioned in the Hadīth refers to all its types of injustice, including polytheism. The Hadīth state that injustice will be an excessive darkness that overwhelms its perpetrator on the Day of Judgment, in such a way that he will not be guided to a path. In the second Hadīth, the Prophet (may Allah's peace and blessings be upon him) said: "And fear miserliness, for it destroyed those who were before you." This statement gives a warning against miserliness, explaining that if it prevails in a community it is considered a sign of its destruction. This is because miserliness is one of the causes of injustice, transgression, aggression, and bloodshed.
Source · Narrated by Muslim - Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).