John the Baptist is not a self-appointed radical who appeared in the wilderness one day and started baptizing. He is not sui generis—quite the opposite. John’s genealogy proves how situated he is within a specific proclamatory and historical context, and it is this context that anoints him as the one who functions appropriately as the Forerunner of Christ. First, he is the cousin of Christ through Elizabeth (Luke 1:36). Second, his father Zacharias was a priest of the temple, famously losing his voice because of his failure to believe God’s promise concerning the birth of a son in his late years (Luke 1:13). Third, his mother Elizabeth was of the house of Aaron, something that gave him the right to perform baptisms (Luke 1:5).
In other words, John the Baptist is fully a member of the priestly class in Israelite society, and functions as such. Even his odd dress and eating habits are an aspect of his calling as a Nazarite (Numbers 6:1-21; Luke 7:33). He himself is doing nothing new. His ministry of baptism and repentance is deeply situated in the customs and religious practices of his community, even if those practices themselves appear radical or challenging. He is, quite simply, the last of the biblical prophets.What is new about John the Baptist is not his station in life or his network of relationships, but his singular focus on the one coming after him. Jesus says to his hearers that John was a “burning and shining light… you were willing to rejoice for a little in his light” (5:35), but then goes on to say, “I have a testimony greater than John’s” (5:36), echoing John 1:8, “He himself was not the light, but he came to testify to the light.” He is the squeak in the hinge of history. The hinge itself is Christ, but a squeak draws attention to a hinge when it is in use. Just so John the Baptist testified to the hinge in a noisy and sacrificially faithful way.