To be honest, there's not a lot you can say in that sort of situation. Whatever you do say is going to be dismissed because you obviously have never read the scripture, have allowed yourself to be deceived by Satan, or are lying for some other rarely specified reason. The variations are endless.
One thing that might be worth pointing out is that if they are so insistent that the OT no longer applies, then we can throw out the Genesis story, most of the commandments (apart from the ones JC could remember, plus the one he made up), all of the Deuteronomy and Leviticus crap about homosexuals and seafood etc. It's never going to be a foolproof strategy, because there are some persistent fools out there.
One thing that might be worth pointing out is that if they are so insistent that the OT no longer applies, then we can throw out the Genesis story, most of the commandments (apart from the ones JC could remember, plus the one he made up), all of the Deuteronomy and Leviticus crap about homosexuals and seafood etc. It's never going to be a foolproof strategy, because there are some persistent fools out there.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'