These next few verses light up commentators, and very different interpretations emerge. As I’ve been pondering this section, I’m noticing a few things, and asking questions:
First, while I’d like to see this ‘impossible’ section as a detour of sorts, there’s nothing immediately obvious in the text to suggest that. Rather, it seems to be part of the on-going discussion this writer is having with his readers–which means interpreting it should be consistent with what has come before and what follows.
Second, repentance was the first item on his list of the elementary teachings about Christ. It’s also what is impossible for those who have once been enlightened, etc. That such people cannot be brought back to repentance is curious: the passive voice (“be brought”) implies an actor other than the one who has turned away. So who would be bringing back to repentance the one who turned: God? another believer? If the latter, then is this writer trying to say it’s OK to focus efforts on those who are genuinely searching for/interested in the Lord, rather than those who jumped in and then later bailed out?
Third, from the way descriptive phrases pile up (been enlightened, tasted the heavenly gift, shared in the Holy Spirit, etc.), it certainly seems like the writer has in mind someone who has made a sincere commitment to and who has had a significant experience with the Lord. John’s awareness of those who ‘went out from us but did not really belong to us’ (1 John 2:19) doesn’t seem to be dealing with this sort of person.
Fourth, I’m intrigued by the ‘parable’ about land and rain (6:7-8), which recalls Jesus’ words about bearing fruit (John 15:8) as well as His parable of the sower. This emphasis on ‘fruit’ as a mark of the God-follower crops up (ha!) several times in Scripture, and here we’re reminded that lasting fruit is the likely and desirable outcome of those who live under God’s ‘rain’.
Fifth, I wonder about the time frame for ‘impossible’.
Sixth, this section offers not simply threat or judgment; surely there is also from this writer a lament over what has happened for those who started well but are leaving the path Jesus marks out. Back to that list–enlightened, tasted, shared, and so on: with these phrases, the writer is telling us about the marvelous blessings of life in Christ. Even as we consider those walking away, we are reminded of all that is available for those whose hearts incline toward the Lord.
Finally, while I’m finishing this post, I’m not done with this passage.