False teachers and ignorant church members often dismiss what Paul wrote because they think he is out-dated or just wrong. They tip their hands by denying that the Holy Spirit was behind the writings. But Paul shows how Christians accept the word of God as what it really is.
1 Thessalonians 2:13 And we also thank God constantly for this, that when you received the word of God, which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers.
So by denying that scripture is scripture they concede their unsaved nature and/or their ignorance.
And Peter teaches that the “ignorant and unstable twist” scriptures “to their own destruction” and how Paul’s writings are scripture (“as they do the other Scriptures”).
2 Peter 3:15–16 And count the patience of our Lord as salvation, just as our beloved brother Paul also wrote to you according to the wisdom given him, as he does in all his letters when he speaks in them of these matters. There are some things in them that are hard to understand, which the ignorant and unstable twist to their own destruction, as they do the other Scriptures.
Of course, the “Christian” Leftists will say that Peter didn’t write 2 Peter and will probably deny that Paul wrote 1 Thessalonians. Such is their predictable lot. But use these passages anyway. Best case is that they are convicted by them. Worst case is that it makes them squirm and honors God by speaking his truths. Either is fine.
Also see Paul vs. Jesus? Not exactly.