John Calvin on 2 Peter 2:16

It may be here asked, by what right Balaam had the name of a prophet, when it appears that he was addicted to many wicked superstitions. To this I reply, that the gift of prophecy was so special, that though he did not worship the true God, and had not true religion, he might yet have been endued with it. Besides, God has sometimes caused prophecy to exist in the midst of idolatry, in order that men might have less excuse.

Now, if any one considers the chief things which Peter says, he will see that his warning is equally suitable to the present age; for it is an evil which prevails everywhere, that men use scurrilous raillery for the purpose of deriding God and the Savior; nay, they ridicule all religion under the cloak of wit; and when addicted, like beasts, to their own lusts, they will mingle with the faithful; they prattle something about the gospel, and yet they prostitute their tongue to the service of the devil, that they may bring the whole world, as far as they can, to eternal perdition. They are in this respect worse than Balaam himself, because they gratuitously pour forth their maledictions, when he, induced by reward, attempted to curse.

2 Peter 2:17-19

17. These are wells without water, clouds that are carried with a tempest; to whom the mist of darkness is reserved for ever.

17. Ii sunt fontes sine aqua, nebulae quae turbine aguntur; quibus caligo tenebrarum in aeternum parata est.

18. For when they speak great swelling words of vanity, they allure through the lusts of the flesh, through much wantonness, those that were clean escaped from them who live in error.

18. Nam ubi plusqum fastuosa vanitatis verba sonuerint, inescant per concupiscentias carnis, lasciviis, eos qui verè aufugerant ab iis qui in errore versantur.

19. While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage.

19. Dum libertatem illis promittunt, quum ipsi sint servi corruptionis: a quo enim quis superatus est, huie in servitutem est addictus.