St.bernard

Saint Bernard (d.1153) said that the piercing of Christ's side revealed his goodness and the charity of his heart for us. The earliest known hymn to the Sacred Heart, "Summi Regis Cor Aveto" is believed to have been written by the Norbertine, Blessed Herman Joseph (d.1241) of Cologne, Germany. This hymn begins: "I hail Thee kingly Heart most high."

From the thirteenth to the sixteenth centuries, the devotion was propagated but it did not seem to have developed in itself. It was everywhere practised by individuals and by different religious congregations, such as the Franciscans, Dominicans, and Carthusians. Among the Franciscans the devotion to the Sacred Heart of Jesus has its champions in Saint Bonaventure (d. 1274) in his Vitis Mystica ("Mystic Vine"), B. John de la Verna and the Franciscan Tertiary Saint Jean Eudes (1602–1680).[6] Bonaventure wrote: "Who is there who would not love this wounded heart? Who would not love in return Him, who loves so much?”[7] It was, nevertheless, a private, individual devotion of the mystical order. Nothing of a general movement had been inaugurated, except for similarities found in the devotion to the Five Holy Wounds by the Franciscans, in which the wound in Jesus's heart figured most prominently.

In the sixteenth century, the devotion passed from the domain of mysticism into that of Christian asceticism. It was established as a devotion with prayers already formulated and special exercises, found in the writings of Lanspergius (d. 1539) of the Carthusians of Cologne; the Benedictine Louis de Blois (d. 1566), Abbot of Liessies in Hainaut, John of Avila (d. 1569) and Francis de Sales (d. 1622).

The historical record from that time shows an early bringing to light of the devotion. Ascetic writers spoke of it, especially those of the Society of Jesus (Jesuits). The image of the Sacred Heart of Jesus was everywhere in evidence, largely due to the Franciscan devotion to the Five Wounds and to the Jesuits placing the image on the title-page of their books and the walls of their churches.

The first to establish the theological basis for the devotion was Polish Jesuit Kasper Drużbicki (1590-1662) in his book Meta cordium - Cor Jesu (The goal of hearts - Heart of Jesus). Not much later Jean Eudes wrote an Office, and promoted a feast for it. Père Eudes was the apostle of the Heart of Mary, but in his devotion to the Immaculate Heart there was a share for the Heart of Jesus. Little by little, the devotion to the two Hearts became distinct, and on August 31, 1670, the first feast of the Sacred Heart was celebrated in the Grand Seminary of Rennes. Coutances followed suit on October 20, a day with which the Eudist feast was from then on to be connected. The feast soon spread to other dioceses, and the devotion was likewise adopted in various religious communities. It gradually came into contact with the devotion begun by Margaret Mary Alacoque at Paray-le-Monial, and the two merged.