For someone living in first century Palestine, water was a matter of life and death. Life, because you couldn't live without it; but death, just as much. Death when it was scarce; death in its terrifying excess when devastating floods came; death in the perils of storms at sea.
We find this ambivalence in many of the Old Testament's famous tales. In the beginning is the chaotic, fearsome void of the waters, but from these all life springs. Later, flood waters devastate the land, drowning man and beast without discrimination, but the same waters bear Noah and his ark to a new life on a verdant land. The waters of the Red Sea part for Moses and lead the Israelites to their promised land, but fall to crush their Egyptian pursuers.
Each of these stories (the Creation, Noah's Ark, the Exodus) make water the symbol of how God takes something deadly and redirects into give new life to His people. God does not destroy the deadly waters, but channels them towards life.
These stories point towards something fundamental about the nature of God's activity in the world, but do not - cannot - go quite far enough. In their own right, they show God using something naturally deadly, water, to a life-giving end. But in Christ, and especially in His Baptism which we celebrate today, the revelation that the Old Testament hints at is realised, fulfilled, as something far more profound. Because as Christ steps into the waters of baptism, He does not just make good use of them, but changes them fundamentally.
Christ, born without sin, did not need cleansing by baptism. Quite the opposite. By descending into the water, dressed in white as though for the grave, He purified it so that it may bring us eternal life. As St Paul writes, we are "buried with (Christ) by baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, so we too might walk in newness of life." Our Lord's baptism is part of the same divine movement by which God the Word came into Creation on Christmas Day, taking the form of sinful man and raising it to sinlessness; part of the same divine movement by which He would later descend from the Cross to the dead and ascend to His Father, lifting death with Him there and so changing it into eternal life.
The Baptism of Our Lord is not just part of the Epiphany season, but an Epiphany itself: in fact, the Orthodox Churches celebrate it as part of Epiphany, dipping the paschal candle three times into the font into bless the baptismal water. And you could say it is a triple Epiphany. It is an Epiphany of God's work in the world, not destroying but perfecting, foreshadowing Christ's work on the Cross, changing death to eternal life; it is an Epiphany of the Holy Spirit, descending on Christ and hallowing Creation, foreshadowing the Pentecost yet to come; it is an Epiphany of Christ's sonship, the first time the Father explicitly names Him Son; and so, it is an Epiphany of the Holy Trinity.
But it is even more than that. It is an Epiphany not just of God's interrelationships, but of our relationship to God too, because just as the Father proclaims Jesus His Son as He steps into the waters, so He offers us the chance to become His adopted children, Jesus' adopted siblings, through the same but purified waters. Most of us here have received that adoption, and it is good practice to remind ourselves of that great privilege. So, I would encourage you whenever you enter or leave the church, but particularly as you leave on this blessed night, to dip your hand into the font and bless yourself with the baptismal water in the name of the Father, the Son and the Holy Spirit, and give thanks that united in Christ's death, you will be united in His Resurrection.