John Calvin Commentary 2 Peter 2:1

"But there arose false prophets also among the people, as among you also there shall be false teachers, who shall privily bring in destructive heresies, denying even the Master that bought them, bringing upon themselves swift destruction." — 2 Peter 2:1 (ASV)

But there were. As weak consciences are usually very severely and dangerously shaken when false teachers arise, who either corrupt or mutilate the doctrine of faith, it was necessary for the Apostle, while seeking to encourage the faithful to persevere, to remove such an offense. Moreover, he comforted those to whom he was writing, and confirmed them by this argument: that God has always tested and proved His Church by such a temptation as this, so that novelty might not disturb their hearts. “The condition of the Church under the gospel,” he says, “will not be different from what it was formerly under the law; false prophets disturbed the ancient Church; the same thing must also be expected by us.”

It was necessary to show this expressly, because many imagined that the Church would enjoy tranquility under the reign of Christ. For as the prophets had promised that at His coming there would be real peace, the highest degree of heavenly wisdom, and the full restoration of all things, they thought that the Church would no longer be exposed to any contests. Let us then remember that the Spirit of God has once for all declared that the Church shall never be free from this internal evil. And let this similarity always be kept in mind: that the trial of our faith is to be similar to that of the fathers, and for the same reason—so that in this way it may be made evident whether we really love God, as we find it written in Deuteronomy 13:3.

But it is not necessary here to refer to every example of this kind; it is enough, in short, to know that, like the fathers, we must contend against false doctrines, and that our faith ought by no means to be shaken on account of discords and sects, because the truth of God shall remain unshaken despite the violent agitations by which Satan often strives to upset all things.

Observe also, that no one time in particular is mentioned by Peter when he says there shall be false teachers, but that all ages are included; for he here makes a comparison between Christians and the ancient people. We ought, then, to apply this truth to our own time, lest, when we see false teachers rising up to oppose the truth of God, this trial should break us down. But the Spirit reminds us, so that we may take more heed; and to the same purpose is the whole description which follows.

He does not, indeed, paint each sect in its own colors, but particularly refers to profane men who manifested contempt towards God. The advice, indeed, is general, that we ought to beware of false teachers; but, at the same time, he selected one kind of them from whom the greater danger arose. What is said here will later become more evident from the words of Jude (Jude 1:4), who treats exactly of the same subject.

Who privily shall bring in. By these words he points out the craftiness of Satan, and of all the ungodly who fight under his banner, that they creep in by indirect ways, as through underground burrows. The godly, then, ought to be more watchful, so that they may escape their hidden frauds: for however they may insinuate themselves, they cannot circumvent those who are carefully vigilant.

He calls them opinions of perdition, or destructive opinions, so that everyone solicitous for his salvation might dread such opinions as the most noxious pests. As to the word opinions or heresies, it has not, without reason, been always deemed infamous and hateful by the children of God; for the bond of holy unity is the simple truth. As soon as we depart from that, nothing remains but dreadful discord.

Even denying the Lord that bought them. Though Christ may be denied in various ways, yet Peter, as I think, refers here to what is expressed by Jude, that is, when the grace of God is turned into lasciviousness. For Christ redeemed us, so that He might have a people separated from all the pollutions of the world, and devoted to holiness and innocence. They, then, who throw off the bridle and give themselves up to all kinds of licentiousness are not unjustly said to deny Christ by whom they have been redeemed. Hence, so that the doctrine of the gospel may remain whole and complete among us, let this be fixed in our minds: that we have been redeemed by Christ, so that He may be the Lord of our life and of our death, and that our main object ought to be to live to Him and to die to Him. He then says that their swift destruction was at hand, lest others should be ensnared by them.