It is reciting Scripture:
Hail Mary, full of grace, the Lord is with you.
Luke 1:28 "And coming to her, he said, "Hail, full of grace, the Lord is with you." Blessed art thou among women
Luke 1:41-42a "When Elizabeth heard Mary's greeting, the infant leaped in her womb, and Elizabeth, filled with the holy Spirit, cried out in a loud voice and said, "Most blessed are you among women..."
Luke 1:48 "For he has looked upon his handmaid's lowliness; behold, from now on will all ages call me blessed."
Blessed is the fruit of your womb, Jesus
Luke 1:42b "and blessed is the fruit of your womb."
Holy Mary, Mother of God
Luke 1:43 "And how does this happen to me, that the mother of my Lord should come to me?
Pray for us sinners, now and at the hour of our death. Amen.
Luke 2:35 "...and you yourself a sword will pierce so that the thoughts of many hearts may be revealed." John 2:5 "His mother said to the servers, "Do whatever he tells you."
Why don't you recite Leviticus?
Frankly if you need to atone for sins by making some sacrifice in reading scripture, I would think that having to recite a few chapters of Leviticus would go a long way further towards making a person think twice about repeating a sin than having to recite a few hundred Hail Marys.
Tell me, as a penance after confession, have you ever been asked to recite a chapter or two from Leviticus?
If so, have you ever repeated THAT sin?