Christmas meant Missional Transformation: Luke 1:76-79
John (Yohanan)’s task is clear: Zechariah tells him, at his birth, that he is to be a prophet who will prepare the way for Someone Else – the Messiah.
John’s life is a life for Another: here is a prophet who, simply because he was a prophet, ought to be given some consideration for heroism, but the words of Zechariah are all shaped to give John a missional life – a life shaped by preparing others for the Messiah. I know of no other prophet with more of a missional focus than John.

Zechariah then specifies what the Messiah’s coming will mean:
The knowledge of salvation.
The forgiveness of sins.
The gift of light and enlightenment.
The path of peace.
It is pious and superficial to look at Zechariah and Elizabeth as parents who “gave their son away” for the work of God – which they no doubt did. It also just as pious and superficial to look at John as little more than an example of a person “who lived for Christ.” The place to begin is to observe that what Zechariah and Elizabeth realize is that the entire sweep of biblical prophecy and history are rolling into a dramatic moment where time will be transferred from BC to AD, from the pre-Messianic age to the Messianic age, from expectation of Kingdom to Kingdom itself, and John plays the crucial role of pointing to the one who will make all this happen. Still, John’s entire life is “missional” as a pointer. And the One to whom he will point will be the one whose mission will be complete, will be hyper-relational, and will bring about what God has promised for his people.
Nolland is suggesting in his commentary in Luke that John’s part in the Benedictus is 1:76-79 while the Messiah’s part (to which John points) is 1:68-75. In fact, John’s part is really only 1:76. I’m not sure I can agree that Zechariah’s praise is so singularly focused on Messiah; instead, I think he is praising God for his son who is destined by God to introduce the messianic salvation.
What happens, though, is this: the Messiah will transform Israel – top to bottom – and it is the “missional” focus of God to bring this about through John’s introduction of Jesus and then, more importantly, through the Messiah’s missional work that provides a template of what God is doing in this world in the Way of Jesus.