There are priests who offer gifts according to the law. They serve a copy and shadow of the heavenly things. . . . Christ has obtained a ministry that is as much more excellent than the old as the covenant he mediates is better, since it is enacted on better promises. . . .
“This is the covenant that I will make . . . I will put my laws into their minds, and write them on their hearts, and I will be their God, and they shall be my people.”
Here we see that Christmas means two things. First, it means the replacement of Old Testament shadows with reality. The temple and sacrifices and priesthood and feasts and dietary laws were all shadows and copies of the reality in heaven. That reality is Jesus Christ and his work as our High Priest and our sacrifice and our focus of worship. Jesus fulfills and replaces the shadows of the Old Testament.
Second, it means that God makes the reality of Christ real to us personally by the work of the new covenant when he writes his truth on our hearts. God moves powerfully into our hearts and minds to overcome our resistance to the beauty of his reality. He writes his will—the truth of the reality of Jesus—on our hearts, so that we see him for who he really is and are willing and eager to trust him and follow him— freely, from the inside out, not slavishly under constraint from outside.
God is just and holy and separated from sinners—sinners like you and me. This is our main problem at Christmas—and every other season. How shall we be put right with a just and holy God? Nevertheless, God is merciful and promised in Jeremiah 31 (five hundred years before Christ came) that someday he would do something new. He would replace shadows with the reality of the Messiah. And he would powerfully move into our lives and write his will on our hearts so that we are not constrained from the outside but are willing from the inside— to love him and trust him and follow him.
That would be the greatest salvation imaginable—if God should offer us the greatest reality in the universe to enjoy and then move in us to see to it that we could enjoy it with the greatest freedom and the greatest pleasure possible. That would be a Christmas gift worth singing about. And that is exactly what he has done.