25. Now to him that is of power--more simply, as in Jude 24, "to Him that is able."
      to stablish--confirm, or uphold
      you, according to my gospel, and the preaching of Jesus Christ--that is, in conformity with the truths of that Gospel which I preach, and not I only, but all to whom has been committed "the preaching of Jesus Christ."
      according to the revelation of the mystery--(See on Ro 11:25).
      which was kept secret since the world began--literally, "which hath been kept in silence during eternal ages."

JFB.