Imam As-Sadiq (a.s.) said:
إذا رَأيْتُمُ الْعَبْدَ يَتَفَقَّدُ الذُّنُوبَ مِنَ النّاسِ ناسِياً لِذَنْبِهِ فَاعْلَمُوا أَنَّهُ قَدْ مُكِرَبِهِ
When you see someone searching for people’s sins and censuring them, but ignoring his own sins, you shall know that he is involved in divine punishment.1
There are a lot of people who are very insolent, vocal and ingenious in criticizing others while they forget and ignore their own state. As the popular proverb says: they see a thorn in the foot of others, but do not see a branch in their own eyes!
Curtains of conceit and unawareness have covered the eyes of such people because they are drowned in sin, self-conceit and selfishness, and are wandering among deviated paths. Those on the right path take care of their own faults before censuring others.