Adam Clarke on 2 Timothy 2:25

Those that oppose - Αντιδιατιθεμενους. This seems to refer to those who opposed the apostle's authority; and hence the propriety of the allusion to the rebellion of Korah and his company. See observations at the end of the chapter.

If God peradventure - He was to use every means which he had reason to believe God might bless; and the apostle intimates that, bad as they were, they were not out of the reach of God's mercy.