There is nothing in the Bible that says public revelations ceased in the time of the Apostles. That is not what that verse means, even according to the scriptural interpretaion that you yorself had given. In that link that you had provided to the Douay-Rheims Bible, it interprets that particular verse as follows:
20 “No prophecy of scripture is made by private interpretation”… This shows plainly that the scriptures are not to be expounded by any one’s private judgment or private spirit, because every part of the holy scriptures were written by men inspired by the Holy Ghost, and declared as such by the Church; therefore they are not to be interpreted but by the Spirit of God, which he hath left, and promised to remain with his Church to guide her in all truth to the end of the world. Some may tell us, that many of our divines interpret the scriptures: they may do so, but they do it always with a submission to the judgment of the Church, and not otherwise.
I generally agree with that interpretation—although I would question that the Catholic or Chaldean churches now have the exclusive right of interpretation—but that does not mean that public revelations have come to an end. Joseph Smith was a prophet like Moses. He came to establish a new dispensation of the gospel, because the old one had apostatized. That right of interpretation now rests with the LDS Church. But that does not mean that public interpretations have come to an end either. The LDS Church has now both the right of interpretation, as well as the right to bring public revelations for the Church as well as for the whole world.
zerinus