John was called the Baptist by friend and foe, because baptism was characteristic of his ministry, recognized even by Herod, calling him John the Baptizer
(ho baptizoon), with the same meaning as the Baptist
(ho baptistès, Matthew 14:2). His baptism was not like the cleansing baths of that day.
It is clear that John was known as the Baptist
from very early on, as the nickname is used in the Gospels as self-evident by both friend and foe. This demonstrates how characteristic baptism was of John’s ministry. Importantly, the nickname also shows that people did not equate his baptism with the many cleansing baths which was common at the time, but which were not performed by the third party, but by the person himself. That the nickname continued to be used as a reference to John’s baptizing activity, and had not degenerated to a meaningless cliché, is clear from Mark 6:14, where Herod speaks about him (in the Greek original) as John the Baptizer
(ho baptizoon), with the same meaning as the Baptist
(ho baptistès, Matthew 14:2).1
1 In those days John the Baptist came preaching in the wilderness of Judea,