John Calvin Commentary 2 Peter 2:3

"And in covetousness shall they with feigned words make merchandise of you: whose sentence now from of old lingereth not, and their destruction slumbereth not." — 2 Peter 2:3 (ASV)

With feigned words. Peter endeavors by all means to render the faithful displeased with ungodly teachers, so that they might resist them more resolutely and steadfastly. It is an especially detestable thing that we should be sold like vile slaves. But he testifies that this happens when anyone seduces us from the redemption of Christ. He calls those feigned words which are artfully formed for the purpose of deceiving.

Unless, then, someone is so foolish as to sell the salvation of his soul to false teachers, let him close every avenue that may lead to their wicked schemes. For the same purpose as before, he repeats again that their destruction is not delayed, that is, so that he might frighten the good from their company. For since they are consigned to sudden destruction, everyone who connects himself with them must also perish with them.