Tulipman
Let’s look at 1 Corinthians 4:10 and see if Paul is being sarcastic.
“We are fools for Christ’s sake, but you are wise in Christ! We are weak, but you are strong! You are distinguished, but we are dishonored!” NKJV
It is fairly clear from the context that Paul is contrasting the apostle’s situation with the situation of his readers. It is also clear that this contrasting was not meant as something his readers should be proud about. He does this not to shame his readers, but to warn them that they need to take up the cross, rather than live safely. (see verse 14)
Is contrasting in order to make his readers see a point sarcasm? To be honest, I would not have seen it that way if I had not read what you said concerning 1 Cor. 4:10. But, in a broad sense of the word “sarcasm”, I can see using this verse as sarcasm.
Now let’s look at 2 Peter 2:1.
“But there were also false prophets among the people, even as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Lord who bought them, and bring on themselves swift destruction.” NKJV
Looking at the context, though admittedly I could be missing something, I do not see any sarcasm. I have looked into the Greek words for “Lord” and “bought” and think there is something to that. However, as yet even after studying this for hours (over the last few days), I have not got a firm grasp on the matter yet. It must be because of age, but that is ok with me until God gives me more light. Years ago, I would literally lose sleep over something like this.
I have concluded that false prophets and false teachers are false Christians and in this case they are within the Church, seeking to lead people away from the truth. As I use the analogy of Scripture, the word “bought” in the redemption sense, does not fit with other Scripture passages that deal with this issue. If it really does mean redeemed, then these false prophets and teachers were Christians who lost their salvation.
This of course would mean that the doctrine of perseverance of the saints is not biblical and as a result the rest of TULIP would fall like a house of cards.
Therefore, mainly because I have such a conviction that all 5 of the doctrine of grace are biblical, is something I reject completely.

Sorry, I wasn't more helpful.

Tom