They that are unlearned and unstable (οἱ ἀμαθεῖς καὶ ἀστήρικτοι)
Both words are peculiar to Peter. On the latter, see on 2Pe 2:14.
Wrest (στρεβλοῦσιν)
Only here in New Testament. Meaning, originally, to hoist with a windlass or screw; to twist or dislocate the limbs on a rack. It is a singularly graphic word applied to the perversion of scripture.
The other scriptures (τὰς λοιπὰς γραφὰς)
Showing that Paul's epistles were ranked as scripture. See on Mar 12:10.