Then Zechariah his father, filled with the holy Spirit, prophesied, saying: "Blessed be the Lord, the God of Israel, for he has visited and brought redemption to his people. He has raised up a horn for our salvation within the house of David his servant, even as he promised through the mouth of his holy prophets from of old: salvation from our enemies and from the hand of all who hate us, to show mercy to our fathers and to be mindful of his holy covenant and of the oath he swore to Abraham our father, and to grant us that, rescued from the hand of enemies, without fear we might worship him in holiness and righteousness before him all our days. And you, child, will be called prophet of the Most High, for you will go before the Lord to prepare his ways, to give his people knowledge of salvation through the forgiveness of their sins, because of the tender mercy of our God by which the daybreak from on high will visit us to shine on those who sit in darkness and death's shadow, to guide our feet into the path of peace." (Lk 1:67-79)
As soon as the speech was returned to Zachariah he prophesied. His prophesies have the following elements. In the prophecy Zachariah blesses God first. Blessing God is the essential element in the prophecy. God is the first and the basis of prophecy. Prophecy is in the name of God. Primacy of God is important.
God is blessed because he has been with the people and he saved the people. God’s presence and his salvific action is another important element in the prophecy. Salvation is from enemies and this done so because God has promised this from the days of Abraham and continued in the days of David and so on. Salvation is historical and factual in time and space and for people.
The child that is born (John the Baptist here and every child in its turn) is called to proclaim this salvation and continue announce this salvation to all the people through forgiveness. Prophecy is also to announce the mercy of God to all the people who are in darkness and thus the people are led in the path of peace.