In the first century it meant the Hebrew scriptures, but for the followers of Christ, it meant all the holy writings...the whole Bible....including all that the apostles wrote after Christ's departure.
Paul was an apostle, taught personally by Jesus like the 12, only post resurrection.....and because his writings form a major part of the NT, they are part of "all scripture". If you believe that God inspired scripture, then you must also believe that his spirit can preserve and protect its authentic content. You haven't thought this through very well, have you?
If Paul was a false prophet, then all Christians who believe his writings are on the road to death. You think God would allow that? God's word is "GOD'S word, so it must be available to all, otherwise he is not being fair to any genuine truth seeker.
Who authorized you or anyone else to accuse Paul of such a thing? If he was accepted by the 12, then God was misleading them too. Is God stupid? A deceiver? Deliberately allowing a false prophet to mislead his worshipers?
Really?
Paul was a self professed apostle, who was a Pharisee, whose message was one of hypocrisy(Romans 7:25), which falls into the category of "beware of the leaven of the Pharisees" (Mt 16:6). His gospel of grace was antithetical to the gospel of the kingdom, and in fact Paul nailed that gospel to his pagan symbol of the cross. As for Paul's word being the wide path to "destruction" (death), look to Matthew 7:13. Paul is the premier false prophet in sheep's clothing (Mt 7:15), whose fruit is rotten (Mt 7:17). It is the "many" who are on the wide path to "destruction", not the few. Those who "dwell on the earth" (Revelation 13:14) are deceived, and already carry the mark of the beast, who was the Roman emperor Constantine, who instituted the Roman church in the year 325 AD at his convened Council of Nicaea. The two horns like a lamb would be the "worthless shepherd" (Zechariah 11:17), Peter and Paul of Zechariah 11:10. As for the bible, the authors of the NT are in doubt, as well as the time of the writings. If the writings do not conform to the Law and the testimonies (OT), they are without dawn/light (Isaiah 8:20). Paul as the tare sown among the wheat was allowed and guarded from destruction by Yeshua in Matthew 13:29-30. The disciples were ordered to leave Paul alone until the "end of the age" (Matthew 13:39). Well we are at the "end of the age" and things are coming to a head. One either comes out of her/daughter of Babylon (Revelation 18:4), or they suffer of her "plagues".