In the time of Jesus Christ He warned His disciples of false teachers that would arise in the Church of God - not long after His death. The Apostle Paul, and others of the Apostles warned of that wolves would enter, or from among the Church's own members false teachers would arise to decide the flock - teaching fables, "smooth things", teaching false doctrine. As Jesus Christ Himself said, there would be those who would come along and say "I, Jesus am the Christ" (not that they were but that Christ was the Christ) and would nonetheless decide many.
It is exactly the same today among the Churches of God, starting on a large scale (as Mr. Armstrong discusses in the sermon) with the now defunct Worldwide Church, but also plainly discernible in several of the off shoot daughter CoGs led by men with quirky doctrinal differences to the "faith once delivered" - hooks by which to entice church members, and others, to them, by means that Mr. Armstrong surveys in the sermon.