The Bible is full of genealogies, and each has its distinctive purpose and function in the context of the book in which it is located, and of the Bible as a whole. So there is nothing unusual about the existence of the genealogical tables of both Mary and Joseph at the birth of Jesus. "Under the guiding hand of God, the Jews preserved their genealogical tables with remarkable accuracy through all the centuries before the birth of Jesus and also during the first century after His birth. Ever since the earliest times the lineage lists were compiled and preserved as accurately as possible. After their return from the Babylonian exile, the Jews again thoroughly fixed their genealogical tables by committing them to writing and bringing them up-to-date, and this was continued until the time of Josephus. Especially would persons like Joseph and the family of Mary, who were of Davidic descent, preserve their genealogical tables with special care because the Old Testament prophesied that the Messiah would be born of the house of David. Apart from the public registers, numbers of Jewish families kept private family trees in their homes and handed them down from generation to generation." - Geldenhuys