God often came to barren women to bring new hope to His people Israel through a child.  Sarah!  Rachel!  Hannah!  Elizabeth!  But Mary was not barren; something entirely new was going to happen in her, something unprecedented in creation.  God was going to touch earth in a new way, becoming flesh and blood.  New creation started inside her body.  Her son will ultimately bring heaven and earth together as one!  The plan will be consummated!

 “The angel answered and said to her, “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; and for that reason the holy Child shall be called the Son of God” Luke 1:35 (NASB).