John 21:23

23.Then this saying went forth. The Evangelist relates that, from misunderstanding Christ’s words, an error arose among the disciples, that John would never die. He means those who were present at that conversation, that is, the Apostles; not that the name brethren belongs to them alone, but that they were the first-fruits, as it were, of that holy union. It is also possible, that, besides the eleven, he refers to others who were at that time in company with them; and by the expression, went forth, he means that this error was spread in all directions; yet probably it was not of long duration, but subsisted among them, until, being enlightened by the Holy Spirit, they formed purer and more correct views of the kingdom of Christ, having laid aside carnal and foolish imaginations. (238)

What John relates about the Apostles happens every day, and we ought not to wonder at it; for if Christ’s disciples, who belonged to his family and were intimately acquainted with him, were so egregiously mistaken, how much more are they liable to fall into mistakes, who have not been so familiarly instructed in the school of Christ? But let us also observe whence this fault arises. The teaching of Christ is useful, and for edification; that is, it is plain; but we obscure the light by our wicked inventions, which we bring to it from our own views. Christ had not intended to pronounce any thing certain or definite about John, but only to affirm that he had full power to decide about his life and death; so that the doctrine is simple and useful in itself, but the disciples imagine and contrive more than had been told them. Accordingly, in order that we may be safe from this danger, let us learn to be wise and to think soberly. But such is the wantonness of the human understanding, that it rushes with all its force into foolishness. The consequence was, that this very error, against which the Evangelist had expressly warned them to be on their guard, continued notwithstanding to gain currency in the world; for a fable has been contrived, that he ordered a ditch to be digged for him, and went down into it, and that next day it was found empty. We see, therefore, that we shall never cease to err, unless we unreservedly receive what the Lord hath taught us, and reject all inventions of men.