What is the ruling on one who openly commits sins then repents and mentions his sins as a lesson, and what is the ruling on one who, among the preachers, informs others of his (the sinner's) circumstances, with or without his knowledge?

A Muslim should not mention their sins that Allah has concealed, whether boastfully or as a lesson, unless there is a pressing need or an overriding benefit. This is based on the Prophet's (peace and blessings be upon him) saying: "All of my Ummah are forgiven except for those who publicize their sins." Publicizing one's sins, thereby exposing Allah's concealment, is forbidden. Moreover, whoever commits a misstep should conceal it and repent between themselves and Allah, due to the severe punishment associated with spreading indecency. A preacher should not name a Muslim when mentioning their transgressions, because concealment is legislatively required, and scholars unanimously agree on the desirability of concealing the faults of believers who are not known for corruption.