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."
A few things to take away from this passage:
- Scripture being hard to understand is not the fault of the interpreter. It teaches things about God which are naturally difficult.
- Paul's letters are Scripture. They are not unique in being hard to understand, nor are they unique in being twisted by false teachers.
- The right understanding of a Scripture is not inaccessible. But it will require effort, and seeking wisdom from God (see James 1:5-8).
- Misunderstanding Scripture doesn't lead to destruction. Twisting it does. (However, an unregenerate heart can't help but twist it.)