2 Pet 2:9

2:9 then the Lord. The implication of the three examples in vv. 4–8 is clear: God will surely judge the wicked and deliver the righteous.

keep . . . under punishment. Some commentators and most English translations see here a reference to preliminary punishment before the final judgment. This is the most natural reading of the Greek, although some commentators including Calvin understand it as a reference to future punishment on Judgment Day (“reserve the unjust for punishment on the day of judgment”). Because Peter’s concern in this passage is the certainty of final judgment, the latter seems more appropriate to the argument than the former.