The Christian Church is a group of Christians who have their own beliefs and forms of worship.

This article addresses the Christian Church broadly, taking account of the variety of conceptions about it, some identifying it with a concrete visible structure (the view of Oriental Orthodoxy, the Eastern Orthodox Church and the Catholic Church), others seeing it as an invisible reality not identified with any earthly structure (the general Protestant view), and others equating it with a particular set of groups that share certain essential elements of doctrine and practice, though divided on other points of doctrine and practice and in government (the branch theory sponsored by some Anglicans).

The Greek term ἐκκλησία, which in its appearances in the New Testament is usually translated as "church", basically means "assembly". This term appears in two verses of the canonical Gospel of Matthew, twenty-four verses of the Acts of the Apostles, fifty-eight verses of the letters of Paul the Apostle (including the earliest instances of its use in relation to a Christian body), two verses of the Letter to the Hebrews, one verse of the Epistle of James, three verses of the Third Epistle of John, and nineteen verses of the Book of Revelation.

The Sacred Heart (also known as Most Sacred Heart of Jesus) is one of the most famous religious devotions to 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.