John's baptism and ritual washings in Judaism

Over at Ragged Glory, I have published another post on Matthew 3:7-12. It explores the question, What was the significance of John's baptism?

I begin with the New Testament data, then consider relevant extra-biblical data, beginning with a passage from Josephus (a first century Jewish historian).

I attempt to demonstrate that John was a theological innovator. His baptism was different from the ritual washings commonly practised by his contemporaries.