The Baptist is all over our Advent celebrations.  Preparing the way for the Christ Luther saw Him as much more than an Old Testament Prophet.  He wrote –

This is the sum and substance of it: In this Gospel (the lesson about the Baptist in the wilderness) is pictured the preacher’s office of the New Testament, what it is, what it does, and what happens to it.

First, it is the voice of one calling, not a piece of writing. The Law and the Old Testament are dead writings, put into books, and the Gospel is to be a living voice. Therefore John is an image, and a type, and also a pioneer, the first of all preachers of the Gospel. He writes nothing, but calls out everything with his living voice.

Secondly, the Old Testament or the Law was preached among the tents at Mount Sinai, to the Jews alone. But John’s voice is heard in the wilderness, freely and openly, under the heavens, before all the world.

Thirdly, it is a calling, clear and loud voice, that is to say, one that speaks boldly and undauntedly and fears no one, neither death, hell, life nor the world, neither devil, man, honor, disgrace nor any creature. Thus Isaiah says in 40, 6ff: “The voice of one saying, cry. And one said, What shall I cry? All flesh is grass, and all the goodliness thereof is as the flower of the field. The grass withereth, the flower fadeth, but the word of our God shall stand forever.” And further: “0 thou that tellest good tidings to Zion, get thee up on a high mountain; lift up thy voice with strength; lift it up, be not afraid.” The world cannot bear the Gospel, and hence there must be a strength, which scorns it and can call against it without fear.