17. But, beloved. To a most ancient prophecy he now adds the admonitions of the apostles, the memory of whom was recent. As to the verb mnh>sqhte, it makes no great difference, whether you read it as declarative or as an exhortation; for the meaning remains the same, that being fortified by the prediction he quotes, they ought to be terrified. By the last time he means that in which the renewed condition of the Church received a fixed form till the end of the world; and it began at the first coming of Christ.
After the usual manner of Scripture, he calls them scoffers who, being inebriated with a profane and impious contempt of God, rush headlong into a brutal contempt of the Divine Being, so that no fear nor reverence keeps them any longer within the limits of duty: as no dread of a future judgment exists in their hearts, so no hope of eternal life. So at this day the world is full of Epicurean despisers of God, who having cast off every fear, madly scoff at the whole doctrine of true religion, regarding it as fabulous.
19. These be they who separate themselves. Some Greek copies have the participle by itself, other copies add eJautou<v, "themselves;" but the meaning is nearly the same. He means that they separated from the Church, because they would not bear the yoke of discipline, as they who indulge the flesh dislike spiritual life. 1 The word sensual, or animal, stands opposed to spiritual, or to the renovation of grace; and hence it means the vicious or corrupt, such as men are when not regenerated. For in that degenerated nature which we derive from Adam, there is nothing but what is gross and earthly; so that no part of us aspires to God, until we are renewed by his Spirit.
1 This is the common interpretation, and yet it seems inconsistent with what is previously said of these men, that they crept in stealthily, and "feasted" with the members of the Church. The eJautou<v, though retained by Griesbach, is excluded by Wetstein and others, being absent from most of the MSS. The verb ajpodiori>zw, means to separate by a boundary two portions from one another, and hence metaphorically to separate or cause divisions: "These be they who cause divisions." They were doing the same thing as those mentioned by Paul in Romans 16:17. They were producing discords in the Church, and not separations from it; and by continuing in it, they became "spots and stains" to its members. -- Ed.