Now that you've had your morning coffee...
A brother comes to you and says "I'm not sure I'll be saved on the Day of Wrath". Is it better to say...
A. "Oh, don't worry, brother, once saved always saved!"
or
B. "The Bible helps us to discern whether or not we belong to Christ and will pass through the coming Judgment safely."
The better answer is B.
Karl seems to have the thinking that if someone is scared about the coming Judgment that you take away those fears by saying to them 'once you are saved you are always saved'. Which is a false and misleading comfort if the person really isn't even saved to begin with.
It's easy to see that his approach is far more dangerous than my approach which would be to have the individual FIRST examine themselves, Biblically, to see if they are even in the faith to begin with. From there you take the appropriate remedy for the person's fear. I see no value in salving the conscience of a person with a OSAS doctrine who isn't even born again to begin with and who, because you told them OSAS is true, are provided no impetus to even determine whether they are or not ahead of the coming Judgment.
Karl's answer to the fear of the coming Judgment in the believer is just another stroking of the ear of the church. The Bible tells us what relieves the fear of the coming Judgment
and it is not "OSAS".