صِنْفَانِ مِنْ أَهْلِ النَّارِ لَمْ أَرَهُمَا: قَوْمٌ مَعَهُمْ سِيَاطٌ كَأَذْنَابِ الْبَقَرِ، يَضْرِبُونَ بِهَا النَّاسَ، وَنِسَاءٌ كَاسِيَاتٌ عَارِيَاتٌ مُمِيلَاتٌ مَائِلَاتٌ، رُؤُوسُهُنَّ كَأَسْنِمَةِ الْبُخْتِ الْمَائِلَةِ. لَا يَدْخُلْنَ الْجَنَّةَ وَلَا يَجِدْنَ رِيحَهَا، وَإِنَّ رِيحَهَا لَتُوجَدُ مِنْ مَسِيرَةِ كَذَا وَكَذَا
Translation: Two groups among the people of the Fire are described: people carrying whips like cattle tails and striking others, and women described as clothed yet uncovered, inclining and causing others to incline, with heads likened to the leaning humps of Bactrian camels. A severe warning is given about their being denied entry to Paradise and its fragrance, although that fragrance can be sensed from afar.
Source: مسلم
صِنْفَانِ is a dual noun meaning two groups. The first group is described as carrying سِيَاطٌ, whips, and striking people. كَأَذْنَابِ الْبَقَرِ compares the shape of the whips to cattle tails.
The central wrong is injustice and abusive physical punishment. Authority should be exercised with justice and restraint, never as personal cruelty or humiliation. Punishment is not a matter of private anger.