Since various Protestants have been known to frequent this blog, maybe they can clear something up for me: Luther famously held Scripture to be the sole guidance to the true Christian ("sola scriptura"), always trumping the supposed authority of the Church. But, of course, just what Scripture consisted of had been decided by... the authority of the Church! (There were many candidates vying for inclusion in the status of being scriptural books, and hot debates about which ones would be so stamped with approval.)
So, once Luther rejects the authority of the Church, how can he insist on just those four gospels being scriptural? What if a Protestant wants to follow, say, the Gospel of Thomas, the Gospel of James, the Gospel of Judas, the Secret Gospel of Mark, the alternative Gospel of Luke, the Diatessaron, or the Gospel of Peter? They all had their adherents back in the day, but were declared infra dig by the authority of the Church. So on what basis can Luther criticize a Protestant who finds one of them "more his style"?