Sacramental union

In Protestant sacramental theology, sacramental union (Latin, unio sacramentalis; Luther's German, Sacramentliche Einigkeit;German, sakramentalische Vereinigung) is the relationship between the outward substance or "sign" of a sacrament (such as the physical washing of water in baptism and the physical elements of the Lord's supper) and the thing signified by the sacrament (such as regeneration and remission of sin in baptism and Christ in the Lord's supper). Lutherans believe the sign and thing signified to be locally united, so that Christ is bodily present at the Lord's supper (see Eucharist in Lutheranism). Reformed Christians believe the sign and thing signified to be inseparable, but to be united spiritually rather than locally and bodily (see Lord's Supper in Reformed theology).

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. It is seen as similar to the personal union in the analogue of the uniting of the two perfect natures in the person of Jesus Christ in which both natures remain distinct: the integrity of the bread and wine remain though united with the body and the blood of Christ.

In the sacramental union the consecrated bread of the Eucharist is united with the body of Christ and the consecrated wine of the Eucharist is united with the blood of Christ by virtue of Christ's original institution with the result that anyone eating and drinking these "elements"—the consecrated bread and wine—really eats and drinks the physical body and blood of Christ as well. Lutherans maintain that what they believe to be the biblical doctrine of the manducatio indignorum ("eating of the unworthy") supports this doctrine as well as any other doctrine affirming the Real Presence. The manducatio indignorum is the contention that even unbelievers eating and drinking in the Eucharist really eat and drink the body and blood of Christ. This view was put forward by Martin Luther in his 1528 Confession Concerning Christ's Supper:

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