We read that once upon a time a rude dunce and dolt happened to be standing in church while people were singing these words:
et homo factus est (and he became human).
He did not take his cap off, bow his knees or accord the words any honor;
but he stood there like a stick, though the entire multitude of the people present had knelt down while these words were being sung in [the Nicene Creed] and offered a devout prayer.
Then the devil stepped up to the man, slapped his mouth so that he saw stars, cursed him terribly, and said:
May the infernal fires consume you, you coarse fool!
If God had assumed my nature and became an angel such as I was,
and people sang: God has become an angel,
I would bow not only my knees to the ground but my whole body, nay, ten ells deep I would crawl into the ground.
But you wretched man stand there like a stick or stone; you hear that God did not become and angel but a man like you, and it's all the same to you...
Now whether this happened or did not happen is neither here nor there.
At any rate, it is in accordance with our faith that the holy fathers wanted to advise young people with an example such as this how great and unspeakable a thing it is that the true Son of God became man.
They wanted us to open our eyes and consider these words well.
(What Luther Says, volume III, Concordia: St. Louis, 1959, p. 1353)