What did Paul say?

[I]t is striking that both the author of 2 Peter and those whom he regards as “ignorant and unstable”(v. 16) seem to share a high regard for Paul’s letters. That is, the author and those other Christians whom he denigrates here disagreed over how to interpret Paul’s letters, but they apparently agreed that they are authoritative texts whose interpretation matters. Clearly, the scriptural status of Paul’s letters was rather widely affirmed across various Christian groups already by the date of 2 Peter (ca. 70–140 AD?), even among Christians who strongly disagreed with one another over other matters of faith.— Destroyer of the gods: Early Christian Distinctiveness in the Roman World, page 114