Mary and Elizabeth

Two women play a crucial role in the coming of the Messiah Jesus.  They are Elizabeth, the mother of John the Baptist and wife of Zacharias, the priest.  And Mary, betroth to Joseph, who becomes the mother of Jesus.  Saint Luke, in the opening pages of his Gospel, tells their story.  Is he privileged to have a very special source for his unique information?  What does his perspective add to our understanding of the earthly life of Jesus?  Of the heavenly origins of Jesus?  What can these two women contribute to our approach to the awesome mystery which is God in the flesh?