"But even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed."
Galatians 1:8 (Words of Paul)
That is the doctrine of the Roman Catholic Church, the LDS Mormon church, the Jehovah Witnesses, Jimmy Swaggart, the 6 to 10 Baptist cults in Appalachia, the Calvinist branch of the Presbyterians, the various Pentecostals, and I could keep on until I wore out my keyboard.