The Sacred Heart (also known as Most Sacred Heart of Jesus) is one of the most widely practiced and well-known devotions, taking Jesus' physical heart as the representation of his divine love for humanity.
This devotion is predominantly used in the Catholic Church and among some high-church Anglicans and Lutherans. The devotion especially emphasizes the unmitigated love, compassion, and long-suffering of the heart of Christ towards humanity. The origin of this devotion in its modern form is derived from a French Roman Catholic nun, Marguerite Marie Alacoque, who said she learned the devotion from Jesus during a mystical experience. Predecessors to the modern devotion arose unmistakably in the Middle Ages in various facets of Catholic mysticism.
In the Roman Catholic tradition, the Sacred Heart has been closely associated with Acts of Reparation to Jesus Christ. In his encyclical Miserentissimus Redemptor, Pope Pius XI stated: "the spirit of expiation or reparation has always had the first and foremost place in the worship given to the Most Sacred Heart of Jesus". The Golden Arrow Prayer directly refers to the Sacred Heart.