When Mary, carrying the baby Jesus in her womb, goes to visit her relative, Elizabeth, it's a powerful moment for both women. Elizabeth is six months pregnant with a baby, John, who would grow up to be John the Baptist. When she hears Mary's voice in greeting, baby John leaps in her womb.
Elizabeth is "filled with the Holy Spirit", and she prophesies. Then Mary, too, is moved, and speaks (or sings?) her own poetic prophesy and praise for God. Mary's exalted prayer has come to be called "The Magnificat", since it begins, "My soul magnifies the Lord."
You can read the story in Luke 1, with Mary's prayer beginning at Luke 1:46. It's been set to music many times. Above, we've linked to one simple but nice example, a chant from one of the New Church liturgies (courtesy of New Church Audio -- composer and musician(s) unknown).
Mary had plans. She was going to marry Joseph. She'd probably been planning her wedding. But now, the angel Gabriel was telling her that she'd been chosen for a very important mission - one that could jeopardize her upcoming marriage, and damage her reputation. And, perhaps most of all, it was a huge responsibility for a young woman, to be the mother of the Messiah.
Mary reacted well. She had the faith and the humility to accept this task, and to do it well. She and Joseph are able to rise to the occasion. Mary goes to visit Elizabeth, too, soon after receiving this news, and together, these two women support each other as they prepare to deliver their babies that will change the world.
There are two passages from Arcana Coelestia which seem especially to bear on this story:
"... what is Divine and the Lord's cannot flow into a proud heart, that is, into a heart full of self-love..." (Arcana Coelestia 9377)
"The angels inhabiting [the] inmost heaven are the wisest of all.... They also love young children far more than even their forebears and mothers do. They are present with infants in the womb... (Arcana Coelestia 5052)
(An acknowledgement: This article was inspired by, and based on, a sermon by Rev. Jared Buss, which you can read at this link. Many thanks for his permission to use it here!)