Pius XII, by his encyclical letter of October 11, 1954 Pius XII, Ineflabilis Deus, the pope ends with:
Let all the children of the Catholic Church, who are so very dear to us, hear these words of ours. With a still more ardent zeal for piety, religion and love, let them continue to venerate, invoke and pray to the most Blessed Virgin Mary, Mother of God, conceived without original sin. Let them fly with utter confidence to this most sweet Mother of mercy and grace in all dangers, difficulties, needs, doubts and fears. Under her guidance, under her patronage, under her kindness and protection, nothing is to be feared; nothing is hopeless. Because, while bearing toward us a truly motherly affection and having in her care the work of our salvation, she is solicitous about the whole human race. And since she has been appointed by God to be the Queen of heaven and earth, and is exalted above all the choirs of angels and saints, and even stands at the right hand of her only-begotten Son, Jesus Christ our Lord, she presents our petitions in a most efficacious manner. What she asks, she obtains. Her pleas can never be unheard.
Given at St. Peter's in Rome, the eighth day of December, 1954, in the eighth year of our pontificate.
Hail Mary, full of Grace!