The historical John, יוחנן, was a thoroughly Jewish religious preacher, who had little if any relation to Jesus and his movement. Here is the story of how John and his central rite, baptism, became part of Christianity.
Originally an allegorical vision about the future return of Judeans to their land, Ezekiel’s vision (ch. 37) becomes one of the cornerstones for the Jewish belief in the resurrection of the dead. The early stages of this development are made clear in a little-known Qumran scroll called Pseudo-Ezekiel.
Leviticus (17:13) requires covering the blood of undomesticated animals; Deuteronomy (12:15) requires pouring out the blood of slaughtered domesticated animals onto the ground. How do these laws reconcile with each other? The sectarians in Qumran have one answer, the rabbis another, the academics a third.