On the octave of the feast of the Assumption, the Church celebrates the Immaculate Heart of Mary.
This liturgical cult was associated with that of the Sacred Heart of Jesus by St. John Eudes in the 17th century. Two centuries later, Popes Pius VII and Pius IX established a feast in the calendar of the universal Church with a proper Mass and Office.
On October 31 and December 8, 1942, Pope Pius XII consecrated the human race to the Immaculate Heart of Mary. Two years later, he established a new office for the Immaculate Heart for the octave day of the Assumption of the Mother of God, August 22.
The Spirit of the Liturgy
Ever since her entry into Heaven, the Heart of Mary continues to intercede for us. The love of her heart is directed first and foremost to God and her Son Jesus, but it also reaches out with motherly solicitude to the entire human race that Jesus entrusted to her during His agony on the Cross.
We therefore praise her for the sublime sanctity of her Immaculate Heart, begging her to obtain for us “the peace of nations, the liberty of the Church, the conversion of sinners, the love of purity and the practice of virtues” (decree May 4, 1944).
The following psalm can be attributed most fittingly to the Heart of Mary:
My heart shall rejoice in Thy salvation: I will sing to the Lord, who giveth me good things: yea I will sing to the name of the Lord the Most High.
This canticle is the Magnificat, in which the Immaculate Virgin glorified the Lord and exulted with joy in God her Savior.