The Feast of the Visitation commemorates the visit of Mary with Elizabeth. (Luke, 1:39–56)
When the Blessed Virgin Mary visits her cousin Elizabeth, they are both pregnant. Mary is pregnant with Jesus and Elizabeth is pregnant with John the Baptist.
Mary left Nazareth as soon as she was told the glorious news by the Archangel Gabriel and went to Hebron, in the hills south of Jerusalem, to visit her cousin Elizabeth.
Even though Jesus was only a zygote at the time, St John the Baptist, in his mother Elizabeth's womb, leapt with joy at his arrival. (Luke 1:44) It was at His presence, that John was cleansed of Original Sin. Elizabeth received the Holy Spirit at this meeting as is testified by Scriptures. (Luke 1:41)
Thus, Scritpures confirms Mary's place as Mediatrix of God's grace. She is not the source of grace but rather the intercessor:
And she cried out with a loud voice and said: Blessed art thou among women and blessed is the fruit of thy womb. And whence is this to me that the mother of my Lord should come to me? (Luk 1:42-43)
Mary, in her joym recites what has subsequently been called The Magnificat:
My soul proclaims the greatness of the Lord,
my spirit rejoices in God my Savior
for he has looked with favor on his lowly servant.
From this day all generations will call me blessed:
the Almighty has done great things for me,
and holy is his Name.
He has mercy on those who fear him
in every generation.
He has shown the strength of his arm,
he has scattered the proud in their conceit.
He has cast down the mighty from their thrones,
and has lifted up the lowly.
He has filled the hungry with good things,
and the rich he has sent away empty.
He has come to the help of his servant Israel
for he has remembered his promise of mercy,
the promise he made to our fathers,
to Abraham and his children for ever.
This feast was kept by the Franciscans before 1263. St Bonaventure recommended it to the entire order and the Franciscan community accepted it.