Most of us here might agree that it is from the primordial version of water whence we came. And so Tillich and others call it reunion. It is universal for human kind. Water is essential to all living things, yet it demands no pay or recognition. Rather it flows humbly to the lowest level.
Nothing is weaker than water, yet for overcoming what is hard and strong, nothing surpasses it.
And John, no wonder, hesitated. No because once he got the spirit, that Spirit drove him to do his work, in this world, to struggle with evil in us, in this world, in order to overcome it. That is the truth in this material world in which we live. Jesus walked into the Jordan to be baptized that day. And by the way, most historical scholars do not deny this.