Word order in general being at the whim of the writer is the bane of the modern learner, although we can be sure that this is a stylistic device and that the spoken word order would have been much more standardised. There's a wonderful line in "The Loom of Language" (wonderful book, wish I could find my copy) berating "the crossword puzzles of Cicero" vs the language he'd use to bawl out his slave.