"This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners..." 1Tim 1:15
Sinner, Jesus Christ came into this world to SAVE you from the guilt, power, consequences and enmity of sin. He came to save sinners, ALL sinners, without exception who would flee to Him to be set free from their sin and be reconciled to God. He did not came to leave you... in your enmity, sin and guilt, but to bring you out of the slavery of sin into the Kingdom of His Son to become a servant of God in Christ.
"But go ye and learn what that meaneth, I will have mercy, and not sacrifice: for I am not come to call the righteous, but sinners to repentance..." Mat 9:13
The issue is here not a matter of "do you know you are a sinner?" No, the issue is really "do you know that you have done nothing else than sin all your life?"
