God, who prepared a fit dwelling place for Holy Spirit, in the Heart of the Blessed Virgin Mary, graciously grant that through her intercession we may be a worthy temple of your glory.
In the midst of the second world war Pope Pius XII put the whole world under the special protection of our Savior’s Mother by consecrating it to her Immaculate Heart, and in 1944 he decreed that in the future the whole Church should celebrate the feast of the Immaculate Heart of Mary. This is not a new devotion. In the seventeenth century, St. John Eudes preached it together with that of the Sacred Heart; in the nineteenth century, Pius VII and Pius IX allowed several churches to celebrate a feast of the Pure Heart of Mary. Pius XII instituted today’s feast of the Immaculate Heart of Mary for the whole Church, so as to obtain by her intercession “peace among nations, freedom for the Church, the conversion of sinners, the love of purity and the practice of virtue” (Decree of May 4, 1944).