Up until recently, the practice has been to do a consecration to the two Hearts separately, first to the Sacred Heart of Jesus, and then to the Heart of Mary. The consecration of the universal Church and the world by the popes marked the culmination of this tradition: in 1899, Leo XIII consecrated the Church and the world to the Sacred Heart of Jesus; in 1942, Venerable Pius XII made a similar consecration of the Church and the world to the Immaculate Heart of Mary; finally, Saint John Paul II renewed this same consecration in 1984 and 2000.
Jesus and Mary are inseparable. That is why we devote and abandon ourselves to both Hearts simultaneously. Through the Holy Spirit, Jesus became man in the womb of the Virgin, where he received a human heart. From the beginning, their two hearts were united in a sacred bond. Mary, a mother and educator, also formed the human heart of her Son.
When the lance of the Roman soldier pierced the heart of Jesus crucified, the heart of Mary was pierced by a sword of sorrow. The Sacred Heart of Jesus is the very reflection of the Heart of His Mother.
In the Church, the devotion to the Heart of Mary and to the Sacred Heart of Jesus evolved in a parallel way. The day after the feast of the Sacred Heart, we remember the Immaculate Heart of Mary, which shows us the very high degree of connection between the two devotions.
In 1916, the angel of peace who appeared three times to the children of Fatima also spoke of the Hearts of Jesus and Mary. The Mother is always near her Son!