Today, when we read the genealogy of Jesus in the liturgy of the Mass, a sentence commonly said in rural areas here in Catalonia, Spain, comes to mind: « Josephs, Johns and donkeys are to be found in every house». That's why, in order to make a difference between them, one uses the household name. Thus, they say, for example, Joseph from Filomena's, John from Josefina's... In this way, a person is easily identified. The problem is that people become branded by the good or bad name of their ancestors. This is what happens with the «Genealogy of Jesus Christ, son of David, son of Abraham» (Mt 1:1).
What Matthew is saying is that Jesus is a real man. In other words, that Jesus —just like every man and every woman who comes into this world— does not start from zero, but brings with him a certain historical baggage. This means that the Incarnation is something deliberate, that when God is made man, He is made man with all the consequences. When he comes to this world, the Son of God, brings with him a family past.
Going down through the characters that make up the list we can see that Jesus —as far as family genealogy goes— does not possess “clean report”. As Cardinal Nguyen van Thuan wrote, «in this world, if a people writes its official history, it will speak of its grandeur... It is a unique, admirable and splendid thing to find a people which, in its official history, does not hide the sins of its ancestors». Sins like homicide (David), idolatry (Solomon) or prostitution (Rahab) appear. Along with these,though, there are moments of grace and of faithfulness to God, especially when we talk of Joseph and Mary, from whom «came Jesus who is called the Christ ¬—the Messiah» (Mt 1:16).
To sum up, Jesus' genealogy helps us contemplate the mystery that we are about to celebrate: that God became Man, true Man, and «he had his tent pitched among us» (Jn 1:14).