Jen Epstein has an interesting post here on Forgiveness. Here is a quote from her article:
"As the offended one, we can forgive the offender, but the offender cannot receive that forgiveness until he repents from the offense to begin with. Luke 17:3-4 adds this aspect to forgiving one another: "If your brother sins against you, rebuke him; and if he repents, forgive him. And if he sins against you seven times in a day, and seven times in a day returns to you, saying, ‘I repent,’ you shall forgive him.” This is not saying that we don't have to forgive unless he repents, as we can clearly see from other passages that we must forgive the offender; but rather that the offender cannot receive our forgiveness until he himself repents. Forgiveness offered is what we must do; forgiveness received is up to the offender."
One reason I think we see so little repentance these days is because people are so desensitized to sin. If you do not catch them with the hand in the cookie jar, they will lie and say they did not touch the jar. (See, the jar was open and they took one out without touching the jar)
Or, some turn it around and act as if there is no 'real' forgiveness if one declines to fellowship with liars and decievers (even though they are forgiven) because they have never even admitted to such things much less repented. How can one have fellowship with darkness?
Our concern should be for their eternal life. After going through the steps of Matthew 18 with no results we must pray for them even though we decline fellowship, but keep the door open for the day they turn away from such sins. To do anything less is to enable and condone sin.
7The one who conquers will have this heritage, and I will be his God and he will be my son. 8But as for the cowardly, the faithless, the detestable, as for murderers, the sexually immoral, sorcerers, idolaters, and all liars, their portion will be in the lake that burns with fire and sulfur, which is the second death."