1 Timothy 1:8-11 8 But we know that the Law is good, if one uses it lawfully, 9realizing the fact that law is not made for a righteous person, but for those who are lawless and rebellious, for the ungodly and sinners, for the unholy and profane, for those who kill their fathers or mothers, for murderers 10 and immoral men and homosexuals and kidnappers and liars and perjurers, and whatever else is contrary to sound teaching, 11 according to the glorious gospel of the blessed God, with which I have been entrusted.
Every follower of Christ needs to witness to love and grace of God that is pouring out of these words. Why was the law given for those who are lawless and rebellious? Verse 11 gives the answer: according to the glorious gospel of the blessed God! Yes, the law is to demonstrate how sinful ALL of us are. Not just "those sinners" over there. Remember, you are the worst sinner you know. But, the reason God wants to show us how sinful we are is so that by His grace we will see how wonderful His Son, Jesus, is. The revelation of our own sinfulness is designed not to beat us down, but to drive us into a relationship with Jesus, the God-man. The law shows us we need a substitute, it doesn't show us "who not to associate with." It certainly doesn't make us feel good about our own moral fiber like we are all "good christian boys and girls." Truthfully, we all suck and Jesus saves us from ourselves. That's the glorious gospel, or good news, that Paul was referring to. That's why the law is there. So, here is a great way of looking at law gospel in your own life:
Law=I really, really suck
Gospel=Jesus is perfect and died in my place to save me from myself, from Satan, and ultimately from the wrath of God.