A hymn by Martin Luther.  From The Lutheran Hymnal of the Evangelical Lutheran Synodical Conference of North America, Concordia Publishing, St. Louis, MO: 1941. #80.

All praise to Thee eternal God
Who, clothed in garb of flesh and blood
Dost take a manger for Thy throne
While worlds on worlds are Thine alone

Once did the skies before Thee bow
A virgin’s arms contain Thee now
While angels, who in Thee rejoice
Now listen for Thine infant voice

A little Child, Thou art our Guest
That weary ones in Thee may rest
Forlorn and lowly is Thy birth
That we may rise to heaven from earth

Thou comest in the darksome night To make us children of the light
To make us in the realms divine
Like Thine own angels, round Thee shine

All this for us Thy love hath done
By this to Thee our love is won
For this our joyful songs we raise
And shout our thanks in ceaseless praise

The incarnation’s purpose: that Christ would come to die as a man, for man’s sin.  To come, as Mark records, to be a ransom for many.  The baby came to die.