To understand the significance that Matthew sees in the events surrounding Christmas, we have to understand what the expectation of Jews, like Matthew, was concerning the Messiah. In fact, this is key to understanding the whole Bible. Matthew carefully lays out this text concerning the genealogy of Jesus for the purpose of presenting Jesus to his mostly Jewish audience as the ultra-Jubilee. There are different ways that Matthew could have laid out the genealogy of Jesus and they wouldn't all work out mathematically the same way, but Matthew is presenting Jesus as the long awaited fulfillment of the promises made to Abraham and so he presents Jesus as the first born in a series of seven sevens, that is, the symbolic year of Jubilee. "(Matthew) arranges the genealogy into three groups of fourteen names-or perhaps we should say, into six groups of seven names. The number seven was and is one of the most powerful symbolic numbers, and to be born at the beginning of the seventh seven in the sequence is clearly to be the climax of the whole list. This birth, Matthew is saying, is what Israel has been waiting for for two thousand years." --N.T. Wright Matthew for Everyone
But if Matthew is presenting Jesus as the ultimate Jubilee, what exactly is a jubilee? Here is what Biblestudy.org has to say about it: The Bible describes a period of time most people have never heard of - the Jubilee year. It occurs after seven sets of seven yearly intervals (49 total) are finished. This proclamation of a fiftieth "liberty" year occurs on one of God's annual feast days known as the Day of Atonement. Because God owns everything, he set up a special, regularly occurring time period where His will is that a man's possessions are returned to him. 10 This fiftieth (Jubilee) year is sacred — it is a time of freedom and of celebration when everyone will receive back their original property, and slaves will return home to their families. 11 This is a year of complete celebration, so don't plant any seed or harvest what your fields or vineyards produce. 39 If one of your brothers becomes indigent and has to sell himself to you, don't make him work as a slave. 40 Treat him as a hired hand or a guest among you. He will work for you until the Jubilee . . . (Leviticus 25) So the year of Jubilee was when your debts were forgiven, slaves were set free, and your inheritance (particularly the land allotted to you by God) was restored to you. This is quite the claim! You may note right away that Israel does not have all of what some people consider "their land" to this date. And that being the case, you may want to argue that Matthew was a bit mistaken to suppose that Jesus was and is the Jubilee. But that is the claim he is making. It begs the question, to what extent does Matthew see the promises fulfilled in Jesus? We will have to keep reading to find out. But it is clear that Matthew is presenting Jesus as the ultra-Jubilee. Expect sins to be forgiven, slaves to be set free, and the holy land to be restored. That's what it means to declare that it is the year of Jubilee.