He is the one who comes after me, who is preferred before me, whose sandal strap I'm not worthy to loosen."

 In the time of John there was a kind of heresy called Gnosticism. Its characteristic was that it was an intellectual and philosophical approach to Christianity. To the Gnostics the simple beliefs of the ordinary Christian were not enough. They tried to construct a philosophic system out of Christianity. They were troubled about the existence of sin and evil and sorrow and suffering in this world, so they worked out a theory to explain it. The theory was this. 