The Gospel reading for today (Luke 1:26-38) tells us of the angel Gabriel coming to Mary to tell her that she would become pregnant with Jesus. Mary's response, despite her hesitation, her fear of the unknown, was "May it be done to me according to your word." It is interesting, isn't it, that God needed human cooperation to fulfill His plan to save us. He needed Mary to say "Yes."
I'm currently reading "His Suffering and Ours" by Kathryn Mulderink. She is an amazing writer and this is an incredible book. It is Lenten themed, focusing on the seven statements of Christ on the cross, which makes an interesting counterpart to our current Advent season. The Christmas event makes the Easter event possible. At the cross, Jesus will remember the woman who said "Yes." (John 19:27) He gives her to us all as our mother. Mulderink offers her own insight into Mary's "Yes":
"She didn't say 'yes' to Gabriel for her own glory; she said 'yes' because she was willing to be used by God for His own purposes, and also because she knew that the salvation of all of creation depended on her 'yes.' She accepted it all, for love of all. . .
We must each utter our own fiat , donate our own bodies, keep our hearts open to Him, so that He can act in the world."