1. Beloved, you have heard the story of this day, how Christ Jesus, God's Son, was born into this world, and what we are to learn from this. Now while this occurred in Bethlehem, according to the Evangelist, the angel of the Lord, accompanied by many thousands of angels, appeared with extremely brilliant light to sing and proclaim this birth to the two or three shepherds in the fields tending their flocks nearby. This was the angel's sermon:
And the angel said to them, "Fear not, for behold, I bring you good news of a great joy that will be for all the people. For unto you is born this day in the city of David a Savior, who is Christ the Lord. And this will be a sign for you: you will find a baby wrapped in swaddling cloths and lying in a manger." (Luke 2:10-12)2. This is the first sermon preached concerning this newborn child, our Lord Jesus. It was delivered for us on earth by the angels from heaven, and even though we deal with this sermon year after year, we still keep on treating it as though new. For even if it were preached and heard every year, yea every day, we could never exhaust its meaning till the end of time.
3. The angel's sermon was indeed most necessary. Christ might have been born a hundred times over, but it would all have been in vain if it had not been preached and revealed to us. What profit would it be to a man to have a treasure and yet not know that he has it? It's like the man who has an inkling about a treasure of gold buried int he cellar of his house but doesn't know for sure how to get at it; what pleasure of joy does he have from it? That is true for everything in this world: A buried treasure is a useless treasure, as the proverb has it, ignotti nulla cupido, "what a person is unaware of doesn't excite him"; there is neither delight nor disgust for what is not real nor likely to come to pass. This is especially true in spiritual matters. If the angels had not proclaimed this holy, wonderfully, joyous birth and revealed this treasure to people, no one would have yearned for this treasure, let alone relished it; none would have rejoiced. The bottom line is, as stated, what a man does not know cannot be dear to him.
4. That is why the truly preeminent point in today's Gospel is that the angel's proclamation made this birth known, to show us this treasure, so that we are not left unawares of having a treasure in hand, unable either to rejoice over it or be comforted by it. Hence the pronouncement: "Fear not: for, behold, I bring you good tidings of great joy."
5. These are truly key words, for the one speaking them is the angel of the Lord. The shepherds are terribly frightened by the great and dazzling light accompanying the angel's appearance and encompassing them with the Lord's brightness in a most unusual happening. In just a split second the dark night was lit up like a fire and everything, heaven and earth, fused together as one mass. The shepherds were hardly accustomed to such a light ands message, and consequently, they were terribly frightened. The angel observes this and, therefore, speaks gently to them, "Fear not," as though to say, you have no reason to fear; but the fact that you do plainly shows that you are not yet aware of the very precious treasure God has given to you, otherwise you would not be afraid but would be of good spirit and happy at heart. That's the reason for which I have come, to make this treasure known unto you. So, listen to me: I bring you joyful tidings, truly joyful, against all your sorrow, fear, and terror.
6. He does not merely say, I make known to you a great work and wonder, but, "I bring you tidings of great joy." Now no one can rejoice over something he does not know about. The man who after being told and informed still refuses to rejoice over it is a fool. The world is full of such fools who have had God's heavenly and eternal gifts proclaimed to them and yet do not rejoice over them, though they know about them. Accordingly the angel does not merely term the birth of our Lord Jesus Christ a wonder, but a joyous thing, for it is his sincere intention to bring a message that would be overpowering, not useless, but avail to make us rejoice over Christ's birth, and not just a little bit but with exceeding joy. The wondrous work of God which I am making known to you, he states, is a birth that will cause you wondrous joy.
7. Here was the reason why: The devil had subjected all mankind under sin and caused terrible, incalculable grief beyond human comprehension. In the first place he precipitated us into original sin, including death with it, and not only death but also all manner of evil. Daily in this world we live with murder, lying, betrayal, stealing, robbing, and all manner of shameful evil, depravity, and vexation, so that literally no one's life or property are safe for a moment, but everything is in terrible turmoil! But beyond such evil there is even a greater one, as God's Word tells, in that the devil takes hold of people so totally that they become mad and foolish. As a result of this wickedness and sin, the human race has become little more that a stinking, shameful, disguised tool of the devil. So despicable has he made mankind through sin that we could not possibly become more base. Eternal death and God's wrath take us by the throat; we are never at peace but constantly plagued in body and soul here on earth, making it an enormous, woeful, fear-ridden kingdom of the devil.
8. If we rightly think about it and weigh one against the other, such pitiful, and heartrending calamity in no way compares with the glory of this precious treasure and joy of a Saviour, who is Christ the Lord, born for us. And with his message the angel wants earnestly to divert our eyes and hearts from our devil-induced grief and sorry condition to this child, purposing thereby like a golden-tongued preacher to show us that the grief and sorrow brought upon us by the devil cannot in any way compare with the salvation and joy that is ours in this newborn child. It is a fact, when this joyous image reigns in a person's heart, then the evil launched by the devil becomes as nothing, though indeed always still very real and damaging.
Klug, Eugene F. A. Sermons of Martin Luther: The House Postils Vol 1. Grand Rapids: Baker Books, 1996.