What are your qualifications to analyze RHClark's posts?
All you have to do is take a deep dive into what the top Greek scholars say about these verses Heb6:4-6 and very similar passages in Heb.10: 26-31 you will see that the admonition is written to Hebrews or in other words Jews who had heard the Gospel of Christ but had rejected it and choose to practice Judaism.
I am sorry no one has ever been educated enough in the scripture to explain it to you before. As you can see when interpreted in this light the passages still agree with salvation by grace through faith. They simply plead with the Jewish people not to reject Christ or suffer damnation.
