The warning passages in Hebrews are often misused and abused because of interpreters’ prior theological commitments. In his commentary on 6:4-8, James Thompson says this:
If the author meant for this passage to disturb his readers, he managed to disturb interpreters throughout the centuries even more, for this passage has been the center of controversy more than any in Hebrews. The missing dimension in the history of interpretation is the recognition that the passage fits the logic of the author’s argument and his relationship to the readers. This passage is one of a series of warnings to the community about the danger that they face (cf. 2:1-4; 3:7-19). The author is neither addressing questions of church discipline nor answering questions about receiving into the community those who lapsed during times of persecution nor addressing post-Reformation questions about the security of the believer. Indeed, the author speaks only to those who have not fallen away. Since this apostasy has not occurred, the author’s words remain hypothetical. His words are intended to shock the readers into recognizing the cost of abandoning God’s heavenly gift (p. 135).
I’m with Thompson enthusiastically until the final two sentences. I think I’m still with him, but I’d want to know if he means that the warnings are merely hypothetical, or that they remain hypothetical until the audience does fall away (if they do), at which point they become actualized.
Scot McKnight posted on the warnings in Hebrews a few months ago, and the warnings were the subject of a longer series of posts on Calvinism in early January.