"Happy is he that condemneth not himself in that things which he alloweth." Romans 14:22 (KJV)
As a minister of the Gospel, it's not enough that you're preaching a message about Jesus Christ; the message must be about His liquid love, the remission of sin that He made possible, and His gift of righteousness to everyone who believes. Don't preach judgment or condemnation; preach His love and righteousness.
When you preach righteousness, people embrace righteousness, and once they do, they start living right. That's because righteousness is a nature; it's the nature of God that's imparted to the spirit of the one who's born again, granting him the ability to live right.
No one can live right, who isn't first made righteous; and only God gives righteousness; it's not something you obtain by your own good works. This is why you should preach the Gospel, for only through the Gospel is the righteousness of God unveiled.
If you don't preach the true Gospel, people will never understand righteousness, and that would defeat the purpose for which Christ came to the world. He came to make men sons of God; He came to make sinners righteous. He came to make us one with the Father, and have His life and nature of righteousness.