Therefore it is a very precious word which we hear: ‘Unto you is born the Savior.’ … Here on earth we will not be able fully to comprehend or learn this sermon. For this life is too narrow and our hearts are too weak. Otherwise, if it were possible that a heart should take it in fully, it would never have any more sorrowful thoughts.
And, if we rightly believed these tidings, this fruit at least should follow, that we would be kind to each other, and leave off lying and deceiving and other vices. But here we see how feeble we are; this joy cannot find a proper entrance into our hearts; we soon forget the preaching both of the angel and of the Savior, and the majority … still run after avarice and other like things, which is a sure indication that we do not regard such preaching or that our faith is too weak; for we would be joyful and free from care, if we believed that we have such a Savior. … Therefore be alarmed on your own account, if you are thus cold and hardened, and earnestly call upon God for grace, that through His Holy Spirit He would change and warm your heart; than place before you this sermon of the angel, think and meditate upon the inexpressible benefit which God confers upon and announces to you through this birth; in order that thereby your heart may be awakened both to repentance and the fear of God, and to faith which comforts itself in this Savior. – Martin Luther, “Second Sermon for Christmas,” Sermons on the Gospels for the Sundays and Principal Festivals of the Church Year by Dr. Martin Luther [House Postil], trans. by Matthias Loy, 1869, v. 1, pp. 102-103.
Quote found in Forum Letter, volume 46, number 12, December 2017