But false prophets also arose among the people, just as there will also be false teachers among you, who will secretly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction upon themselves.
I had not realized the challenge this verse seems to present to the doctrines of Limited Atonement and/or Perseverance of the Saints, but Brown explained it well. Notice that here Peter seems to explicitly say that the "false teachers" were "bought" by "the Master," bringing destruction upon themselves. Limited Atonement and Perseverance of the Saints together assert that Jesus died only for the elect (and not every human being) and that the elect will forever remain in Christ through faith, but this verse seems to suggest that Jesus died even for those false teachers who once were among the believers but later denied Christ.
This seemed to me to be a pretty formidable challenge, and so I waited anxiously to hear Dr. White's response, and thereafter did some additional research. I no longer think this particular challenge is very persuasive, and here's why.