Ask a Greek grammarian and they would tell you that the two letters of Peter are entirely different. One is in a crude sort of Greek that would be typical of an Hebrew fisherman. The other is refined, articulate, in language that is clearly from a linguist who would have been writing what Peter was dictating. THus the writer was using his own style and grammar, thus interpreting the thoughts of Paul (inspired by the Spirit). Same with all the writers of the Bible.
The gospels are another good example. In some instances where different writers are describing the same event, each one is different and in a sense contradict the others. But police love this when witnesses all differ when viewing the same crime. They all come with a different perspective and thought on the events they witness and thus bring stronger testimony to the validity of what they see. If they all agreed in every detail, the police would immediately suspect they have colluded together to bring a contrived view. Therefore, the different witness in scripture is evidence to its veracity.
