How Did Elizabeth Know?

One of my favorite Christmas songs is "Mary Did You Know?" Against the backdrop of a haunting melody, the song gently asks Mary if she knew her baby boy would one day walk on water and was the Great I AM. 


Of course, we cannot know what exactly Mary knew. We know she had been told her baby would be called the Son of the Most High and would reign over the house of Jacob forever. We know from her song that she knew the many mighty deeds God had done for Israel and His unending faithfulness to His people. And we know that she praised God as she submitted herself to His work in her life.


But did she really know that her baby would save our sons and daughters? Did she KNOW that he was Lord of all creation?


Intriguing questions, to be sure, accompanied by a similarly intriguing question which the Luke narrative of Jesus' birth brings to my mind: How did Elizabeth know? 


During a conversation earlier tonight over the Magnificat I noticed that Elizabeth seemed to know something the others did not; yet we have no record of an angelic visit to Elizabeth and Gabriel doesn't tell Zechariah that his wife's cousin's baby would be the Lord his son would be making the way for.


Nonetheless, when Elizabeth sees Mary coming she is filled with the Holy Spirit, feels her own babe move within her womb, and exclaims:

Blessed are you among women, and blessed is the child you will bear! But why am I so favored, that the mother of my Lord should come to me?    --Luke 1:42b-43

How did Elizabeth know that Mary was the mother of her Lord?