In Sermon (138), Imam Ali (a.s.) emphasizes the importance of prohibiting backbiting and fault-finding. This sermon was delivered during a time when societal morals were declining, and people were increasingly engaging in criticizing one another. The Imam addresses those who consider themselves faultless and highlight the mistakes of others.

He states that those whose hands are clean from sins should have compassion for sinners and express gratitude to Allah for keeping them safe from sins. This gratitude should prevent them from exposing the faults of others. This message is significant as it reminds us to reflect on our own state before judging others.

Furthermore, the Imam points out that if a person commits sins themselves, they should refrain from criticizing others. This serves as a reminder that we are all human and susceptible to sin. The sermon underscores the importance of self-reflection before pointing out the faults of others.

Another key aspect of this sermon is the Imam's assertion that even if one has committed minor sins, backbiting is still a grave sin. This teaches us that we should focus on correcting our own mistakes rather than highlighting the mistakes of others.

In conclusion, Imam Ali (a.s.) advises that anyone aware of the faults of others should refrain from expressing them. This ethical principle leads us towards social harmony and love.

From this sermon, we learn the lesson of avoiding the exposure of others' faults and focusing on our own improvement.