The gospel lesson for this week is Luke 3.1-6, which is Luke's account of the ministry of John the Baptist. Luke associates John the Baptist's call to repentance with a familiar text from the Prophet Isaiah: "prepare the way of the Lord, make his paths straight; every valley and hill shall be made low and the rough places smooth."
The fact that the author of Luke's gospel saw the ministry of John the Baptist reflected in Isaiah's vision tells us a lot about the nature of biblical prophecy, and undermines our conventional understandings of prophecy. We normally interpret biblical prophecy in a literal manner, and also associate it with violence that God will bring upon human beings. Here, Luke saw Isaiah's vision as being brought about symbolically and figuratively. John the Baptist's ministry did not include, literally, mountains and hills being made law or rough places being made smooth. Instead, by calling people to repentance, he was figuratively facilitating a way for God to enter into his listener's minds and hearts.
A God who has the power to transform our hearts and minds and to make us holy is a God of greater power than a God whose primary concern is physical manifestations and violence. In fact, through human technology we now have the power and the capacity to literally make rough places smooth and to level hills and valleys. We even have the power to destroy our planet. If God's power is primarily revealed through physical manifestations, then God's demonstration of power is no greater than human technology. Only through God can the rough places of our hearts and minds be made level. Human technology cannot do that and will never be able to do that.
Contrary to traditional understandings, the value of texts like Isaiah's vision of hills and valleys is not about predicting future events, but in revealing the nature of the God who was, is, and is to come. God is concerned with transforming people from children of darkness to children of light, and to make this world a place free of violence and darkness. Isaiah saw the nature of this God in his own time in his own prophetic vision. This God was present in the time of John the Baptist, calling people to repentance. This God is present in our own time calling us to turn away from darkness and live as children of light.