Book of ConcordThe Book of Concord (1580) or Concordia (often referred to as the Lutheran Confessions) is the historic doctrinal standard of the Lutheran Church, consisting of ten credal documents recognized as authoritative in Lutheranism since the 16th century. They are also known as the symbolical books of the Evangelical Lutheran Church. The Book of Concord was published in German on June 25, 1580, in Dresden, the fiftieth anniversary of the presentation of the Augsburg Confession to Emperor Charles V at the Diet of Augsburg.
Sacramental unionSacramental union (Latin: unio sacramentalis; Martin Luther's German: Sacramentliche Einigkeit; German: sakramentalische Vereinigung) is the Lutheran theological doctrine of the Real Presence of the body and blood of Christ in the Christian Eucharist (see Eucharist in Lutheranism). The sacramental union is distinguished from the other "unions" in theology like the "personal union" of the two natures in Jesus Christ, the "mystical union" of Christ and his Church, and the "natural union" in the human person of body and soul.
General revelationIn theology, general revelation, or natural revelation, refers to God's revelation "made to all men everywhere", discovered through natural means, such as observation of nature (the physical universe), philosophy, and reasoning. Christian theologians use the term to describe knowledge of God purported to be plainly available to all mankind. General revelation is usually understood to pertain to outward temporal events that are experienced within the world or the physical universe.
Assurance (theology)As a general term in theological use, assurance refers to a believer's confidence in God, God's response to prayer, and the hope of eternal salvation. In Protestant Christian doctrine, the term "assurance", also known as the Witness of the Spirit, affirms that the inner witness of the Holy Spirit allows the Christian disciple to know that he or she is justified. Based on the writings of St. Augustine of Hippo, assurance was historically an important doctrine in Lutheranism and Calvinism, and remains a distinguishing doctrine of Methodism and Quakerism, although there are differences among these Christian traditions.