A.T. Robertson Commentary 2 Peter 3:16

"as also in all [his] epistles, speaking in them of these things; wherein are some things hard to be understood, which the ignorant and unstedfast wrest, as [they do] also the other scriptures, unto their own destruction." — 2 Peter 3:16 (ASV)

As also in all his epistles (ως κα εν πασαις επιστολαις). We do not know to how many Peter here refers. There is no difficulty in supposing that Peter "received every one of St. Paul's Epistles within a month or two of its publication" (Bigg). And yet Peter does not here assert the formation of a canon of Paul's Epistles.

Speaking in them of these things (λαλων εν αυταις περ τουτων). Present active participle of λαλεω. That is to say, Paul also wrote about the second coming of Christ, as is obviously true.

Hard to be understood (δυσνοητα). Late verbal from δυς and νοεω (in Aristotle, Lucian, Diog. Laert.), here only in N.T. We know that the Thessalonians persisted in misrepresenting Paul on this very subject of the second coming as Hymenaeus and Philetus did about the resurrection (2 Timothy 2:17) and Spitta holds that Paul's teaching about grace was twisted to mean moral laxity like Ga 3:10; Romans 3:20,28; 5:20 (with which cf. 6:1 as a case in point), etc. Peter does not say that he himself did not understand Paul on the subject of faith and freedom.

Unlearned (αμαθεις). Old word (alpha privative and μανθανω to learn), ignorant, here only in N.T.

Unsteadfast (αστηρικτο). See on 2:14.

Wrest (στρεβλουσιν). Present active indicative of στρεβλοω, old verb (from στρεβλος twisted, στρεφω, to turn), here only in N.T.

The other scriptures (τας λοιπας γραφας). There is no doubt that the apostles claimed to speak by the help of the Holy Spirit (1 Thessalonians 5:27; Colossians 4:16) just as the prophets of old did (2 Peter 1:20f.). Note λοιπας (rest) here rather than αλλας (other). Peter thus puts Paul's Epistles on the same plane with the O.T., which was also misused (Matthew 5:21–44; Matthew 15:3–6; Matthew 19:3–10).