I fail to see what Peter said that did not align with Paul ? Matter of fact, Peter said that ignorant and unstable people distort some of Paul's writings, as they do other scriptures to their own destruction. Peter does not contrast with Paul "because some of Paul's writings can be hard to understand". Peter agrees with Paul by stating that "the ignorant and unstable" do the same thing with Paul's writings that they do with other scriptures .... to their own destruction. Straightforward as straightforward can be.
2 Peter 3:14-18
[SUP]14 [/SUP]So then, dear friends, since you are looking forward to this, make every effort to be found spotless, blameless and at peace with him. [SUP]15 [/SUP]Bear in mind that our Lord’s patience means salvation, just as our dear brother Paul also wrote you with the wisdom that God gave him. [SUP]16 [/SUP]He writes the same way in all his letters, speaking in them of these matters. His letters contain some things that are hard to understand, which ignorant and unstable people distort, as they do the other Scriptures, to their own destruction.
[SUP]17 [/SUP]Therefore, dear friends, since you have been forewarned, be on your guard so that you may not be carried away by the error of the lawless and fall from your secure position. [SUP]18 [/SUP]But grow in the grace and knowledge of our Lord and Savior Jesus Christ. To him be glory both now and forever! Amen.