Ibn Sireen on Sin: The biggest sinners always mention other people’s sins

Hisham ibn Hassan reported: Muhammad ibn Sireen, may Allah have mercy on him, said, “We used to say that the people with the most faults are the quickest of them to mention the faults of others.”

Source: al-Ṣamt li Ibn Abī Dunyā 138

عَنْ هِشَامِ بْنِ حَسَّانَ عَنْ مُحَمَّدِ بْنِ سِيرِينَ رحمه الله قَالَ كُنَّا نُحَدِّثُ أَنَّ أَكْثَرَ النَّاسِ خَطَايَا أَفْرَغُهُمْ لِذِكْرِ خَطَايَا النَّاسِ

138 الصمت لابن أبي الدنيا