When the gospel was preached at Corinth, those who were fornicators, adulterers, and homosexuals stopped practicing those sins. "Such were some of you" (I Corinthians 6:8-11). Did the preachers actually preach against those lifestyle choices? Did no one worry that this kind of preaching was not politically correct?
Are people being convicted of sin in our preaching of the gospel today? How will people know they need the remedy of sin in Jesus if they do not first know what sin is and how serious a malady it is?
Some at Corinth were thieves, covetous, and drunkards, but the preaching of the gospel made them realize they needed to quit. Some were revilers and extortioners, but the gospel made them want to quit that lifestyle.
Why the change? Because the gospel is about the remedy for sin, and sin is identified so that people realize it is wrong, and they are brought to realize that if they do not cease the practice of sin they are choosing eternal separation from God. Sin still separates us from God, but if we repent of sin, we can be forgiven and reconciled back to God (Luke 13:3; Acts 2:38; 3:19; 17:30-31).
Change comes by identifying the problem and offering the solution. The gospel does both, and that is why "such were some of you" instead of "such are some of you." We need to identify sin today in preaching the truth of the gospel. Souls are at stake, and we are the watchmen in charge of warning and telling solutions.