John Bergsma has an excellent post (the comment box of which I can’t seem to get to work) comparing the variations in style in Plato’s works to those in the Pentateuch and the Pauline Epistles. On the later:
Several of Paul’s epistles are dismissed as “deutero-Pauline” because of differences in style. Are these differences more dramatic than the differences between Plato’s compositions? Could Paul’s style have changed with age and circumstance?
I have often thought the same thing with reference to Robert Louis Stevenson; surely there is more variation of style between A Child’s Garden of Verses and the The Master of Ballantrae than between Romans and 2 Timothy.