Re Peter being sarcastic, John MacArther agrees that Peter is being sarcastic in the MacArthur Study Bible at 2 Peter 2:1:

." Doctrinally, this analogy can be viewed as responsibility for submission to God which the false teachers had refused. Beyond this, they are probably claiming that they were Christians," and "that the Lord had bought them actually and personally. With some sarcasm, Peter mocks such a claim by writing of their coming damnation. Thus, the passage is describing the sinister character of the false teachers who claim Christ, but deny His lordship over their lives."
(John MacArthur, MacArthur Study Bible, Nashville:Word, 1997)


While MacArthur and I seem to be in agreement that Peter is applying sarcasm here, we're not entirely agreed on how he does it. MacArthur suggests it's "by writing of their coming damnation." Applying damnation as the future state of the reprobate is not sarcasm per se, it's a straight-up warning or point of fact. When those reprobate are claiming at the same time to be Christians, then speaking of their coming damnation would actually be termed irony...it is ironic that they preach of being saved yet are going to hell. That's not sarcasm. Sarcasm involves irony, but it is irony pointed as an insult. Calling a false teacher "bought' when he isn't, like Paul calling the Corinthians "wise" when they were being foolish, is sarcasm.

I think if MacArthur had slid his commentary about sarcasm here right onto the sarcastic point, he would have made a solid observation....he seems to sense it anyway, and he notes the irony in Peter's language.

Interestingly, though, MacArthur sides with Johan's view. I think it's because MacArthur misses the irony point, which leaves him having to explain the use of 'bought'. If you don't think it's sarcasm, then you need to come up with something that accounts for it.

His comment is:

2 Peter 2:1" 'who bought them.' The terms which Peter used here are more analogical than theological, speaking of a human master over a household. The master bought slaves, and the slaves owed the master allegiance as their sovereign. (For an OT parallel, see Deut. 32:5,6, where God is said to have bought Israel, though they rejected Him.) Doctrinally, this analogy can be viewed as responsibility for submission to God which the false teachers had refused. Beyond this, they are probably claiming that they were Christians," and "that the Lord had bought them actually and personally. With some sarcasm, Peter mocks such a claim by writing of their coming damnation. Thus, the passage is describing the sinister character of the false teachers who claim Christ, but deny His lordship over their lives."

If I managed to pursuade MacArthur that Peter's sarcasm was over his use of "bought" and not over his threat of damnation, then there would be no further need to show how "bought" refers to a non-redemptive 'bought', since Peter applied the redemptive use of the word and means it only sarcastically. Remove the redemptive use of the word and make it that commercial, non-redemptive use, there is no sarcasm at all.

But on that view, that agorazo means a non-redemptive use as applicable here just as in Deuteronomy, I just find it very awkward that in New Testament times (remember, the old covenant had now passed) that while these false brethren are walking around saying they are Christians, bought by the blood of Christ who paid the price for their sin, Peter would write New Testament Scripture using a different word than the Septuagint uses in Deuteronomy, (though I appreciate they are sometimes used interchangeably) to invoke an old covenant understanding of 'bought', a reference back to how Israelites under the Old Covenant could be 'bought' and then fall away. In that interpretation of 2 Peter 2:1, Peter is invoking an old covenant use of the word to Jewish false teachers who are no longer even covered under the old covenant, which has passed away by time of Peter's writing. In the economy of the new covenant in Christ's blood, it is no longer sufficient to speak of being bought and purchased but then able to fall away, as we've discussed ( including Jeremiah 31:31-34).

So I suppose even if he is using it in that sense, he is still being sarcastic, isn't he ;-)