I realize what I am and praise you for it. Come to my aid, that I may not stray from the way of salvation.
(Sermo 67, 9)
When did the Lord want to show himself? At the breaking of the bread. We can be sure of that: by sharing the bread, we recognize the Lord.
Mary was happy because she listened and kept God's word. She kept the truth in her spirit more than in the flesh of her womb.