I think the idea is let them see what the Gospel (Jesus) has done for US. This is what I WAS, this is now what I am. Especially if they knew you before being born again. I WAS a sinner,... drunkard, fornicator gossiper, fill in the blank, who didn't love people. But I was miserable and lost. NOW, I have a hope and joy because of who Jesus is, and what He has done for me and to me.
They don't need me to tell them they are filthy sinners. Before Jesus sent the Holy Spirit they needed to be told that they were sinners. Unless their conscience is seared, they KNOW they need a Savior. John 16:[FONT="]7 Nevertheless I tell you the truth. It is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I depart, I will send Him to you. [/FONT][FONT="][/FONT][FONT="]8 And when He has come, He will convict the world of sin, and of righteousness, and of judgment: [/FONT][FONT="][/FONT][FONT="]9 of sin, because they do not believe in Me; [/FONT][FONT="][/FONT][FONT="]10 of righteousness, because I go to My Father and you see Me no more; [/FONT][FONT="][/FONT][FONT="]11 of judgment, because the ruler of this world is judged.
[/FONT] Now they need to see Him in US, so that they desire Him too.
So let's give them the Gospel and pray they accept it.