But that which ye have already,.... Which was something good, even the faithful word, the form of sound words, the mystery and doctrine of faith; this they had received from Christ and his apostles; they had it in their hearts, and a comfortable experience of the truth and power of it, and had made a profession of it, which they now held, and are here exhorted to hold fast: hold fast till I come; meaning the coming of Christ, either at the Reformation by Luther, Calvin, and others, which began at the close of this church state, when the hands and hearts of those professors would be more strengthened, which seems to be the first sense of the words; or to judge Jezebel, destroy antichrist, which will be by the brightness of his coming; till which time the doctrine of the Gospel is to be held fast: and such an exhortation will be always necessary, since, till then, there will be always more or less an opposition to it, and attempts made to wrest it out of the hands of its professors, to cause them to hesitate about it, and to intimidate them in the profession of it, by loading them with reproaches, calumnies, and persecution.