linguistic:paraphrasing, information:highlighting
Christianity

In Nicene Christianity, God became incarnate as Jesus, sacrificing his son to accomplish the reconciliation of God and humanity, which had separated itself from God through sin (see the concept of original sin). According to a view that has featured prominently in Western theology since early in the 2nd millennium, God's justice required an atonement for sin from humanity if human beings were to be restored to their place in creation and saved from damnation. However, God knew limited human beings could not make sufficient atonement, for humanity's offense to God was infinite, so God created a covenant with Abraham, which he fulfilled when he sent his only Son to become the sacrifice for the broken covenant. According to this theology, Christ's sacrifice replaced the insufficient animal sacrifice of the Old Covenant; Christ the " Lamb of God " replaced the lambs' sacrifice of the ancient Korban Todah (the Rite of Thanksgiving), chief of which is the Passover in the Mosaic law.

In the Roman Catholic Church, the Eastern Orthodox Churches, the Lutheran Churches, the Methodist Churches, and the Irvingian Churches, the Eucharist or Mass, as well as the Divine Liturgy of the Eastern Catholic Churches and Eastern Orthodox Church, is seen as a sacrifice. Among the Anglicans the words of the liturgy make explicit that the Eucharist is a sacrifice of praise and thanksgiving and is a material offering to God in union with Christ using such words, as "with these thy holy gifts which we now offer unto Thee" (1789 BCP) or "presenting to you from the gifts you have given us we offer you these gifts" (Prayer D BCP 1976) as clearly evidenced in the revised Books of Common Prayer from 1789 in which the theology of Eucharist was moved closer to the Catholic position. Likewise, the United Methodist Church in its Eucharistic liturgy contains the words "Let us offer ourselves and our gifts to God" (A Service of Word and Table I). The United Methodist Church officially teaches that "Holy Communion is a type of sacrifice" that re-presents, rather than repeats the sacrifice of Christ on the Cross; She further proclaims that:

We also present ourselves as sacrifice in union with Christ (Romans 12:1; 1 Peter 2:5) to be used by God in the work of redemption, reconciliation, and justice. In the Great Thanksgiving, the church prays: "We offer ourselves in praise and thanksgiving as a holy and living sacrifice, in union with Christ's offering for us..." (UMH; page 10).

A formal statement by the USCCB affirms that "Methodists and Catholics agree that the sacrificial language of the Eucharistic celebration refers to 'the sacrifice of Christ once-for-all,' to 'our pleading of that sacrifice here and now,' to 'our offering of the sacrifice of praise and thanksgiving,' and to 'our sacrifice of ourselves in union with Christ who offered himself to the Father.'"

Roman Catholic theology speaks of the Eucharist not being a separate or additional sacrifice to that of Christ on the cross; it is rather exactly the same sacrifice, which transcends time and space ("the Lamb slain from the foundation of the world" – Rev. 13:8), renewed and made present, the only distinction being that it is offered in an unbloody manner. The sacrifice is made present without Christ dying or being crucified again; it is a re-presentation of the "once and for all" sacrifice of Calvary by the now risen Christ, who continues to offer himself and what he has done on the cross as an oblation to the Father. The complete identification of the Mass with the sacrifice of the cross is found in Christ's words at the last supper over the bread and wine: "This is my body, which is given up for you," and "This is my blood of the new covenant, which is shed...unto the forgiveness of sins." The bread and wine, offered by Melchizedek in sacrifice in the old covenant (Genesis 14:18; Psalm 110:4), are transformed through the Mass into the body and blood of Christ (see transubstantiation; note: the Orthodox Church and Methodist Church do not hold as dogma, as do Catholics, the doctrine of transubstantiation, preferring rather to not make an assertion regarding the "how" of the sacraments), and the offering becomes one with that of Christ on the cross. In the Mass as on the cross, Christ is both priest (offering the sacrifice) and victim (the sacrifice he offers is himself), though in the Mass in the former capacity he works through a solely human priest who is joined to him through the sacrament of Holy Orders and thus shares in Christ's priesthood as do all who are baptized into the death and resurrection of Jesus, the Christ. Through the Mass, the effects of the one sacrifice of the cross can be understood as working toward the redemption of those present, for their specific intentions and prayers, and to assisting the souls in purgatory. For Catholics, the theology of sacrifice has seen considerable change as the result of historical and scriptural studies. For Lutherans, the Eucharist is a "sacrifice of thanksgiving and praise…in that by giving thanks a person acknowledges that he or she is in need of the gift and that his or her situation will change only by receiving the gift". The Irvingian Churches, teach the "real presence of the sacrifice of Jesus Christ in Holy Communion":

In Holy Communion, it is not only the body and blood of Christ, but also His sacrifice itself, that are truly present. However, this sacrifice has only been brought once and is not repeated in Holy Communion. Neither is Holy Communion merely a reminder of the sacrifice. Rather, during the celebration of Holy Communion, Jesus Christ is in the midst of the congregation as the crucified, risen, and returning Lord. Thus His once-brought sacrifice is also present in that its effect grants the individual access to salvation. In this way, the celebration of Holy Communion causes the partakers to repeatedly envision the sacrificial death of the Lord, which enables them to proclaim it with conviction (1 Corinthians 11: 26). —¶8.2.13, The Catechism of the New Apostolic Church

The concept of self-sacrifice and martyrs are central to Christianity. Often found in Roman Catholicism is the idea of joining one's own life and sufferings to the sacrifice of Christ on the cross. Thus one can offer up involuntary suffering, such as illness, or purposefully embrace suffering in acts of penance. Some Protestants criticize this as a denial of the all-sufficiency of Christ's sacrifice, but according to Roman Catholic interpretation it finds support in St. Paul: "Now I rejoice in my sufferings for your sake, and in my flesh I complete what is lacking in Christ's afflictions for the sake of his body, that is, the church" (Col 1:24). Pope John Paul II explained in his Apostolic Letter Salvifici Doloris (11 February 1984):

In the Cross of Christ not only is the Redemption accomplished through suffering, but also human suffering itself has been redeemed....Every man has his own share in the Redemption. Each one is also called to share in that suffering through which the Redemption was accomplished....In bringing about the Redemption through suffering, Christ has also raised human suffering to the level of the Redemption. Thus each man, in his suffering, can also become a sharer in the redemptive suffering of Christ....The sufferings of Christ created the good of the world's redemption. This good in itself is inexhaustible and infinite. No man can add anything to it. But at the same time, in the mystery of the Church as his Body, Christ has in a sense opened his own redemptive suffering to all human suffering" (Salvifici Doloris 19; 24).

Some Christians reject the idea of the Eucharist as a sacrifice, inclining to see it as merely a holy meal (even if they believe in a form of the real presence of Christ in the bread and wine, as Reformed Christians do). The more recent the origin of a particular tradition, the less emphasis is placed on the sacrificial nature of the Eucharist. The Roman Catholic response is that the sacrifice of the Mass in the New Covenant is that one sacrifice for sins on the cross which transcends time offered in an unbloody manner, as discussed above, and that Christ is the real priest at every Mass working through mere human beings to whom he has granted the grace of a share in his priesthood. As priest carries connotations of "one who offers sacrifice", some Protestants, with the exception of Lutherans and Anglicans, usually do not use it for their clergy. Evangelical Protestantism emphasizes the importance of a decision to accept Christ's sacrifice on the Cross consciously and personally as atonement for one's individual sins if one is to be saved—this is known as "accepting Christ as one's personal Lord and Savior".

The Eastern Orthodox Churches see the celebration of the Eucharist as a continuation, rather than a reenactment, of the Last Supper, as Fr. John Matusiak (of the OCA) says: "The Liturgy is not so much a reenactment of the Mystical Supper or these events as it is a continuation of these events, which are beyond time and space. The Orthodox also see the Eucharistic Liturgy as a bloodless sacrifice, during which the bread and wine we offer to God become the Body and Blood of Jesus Christ through the descent and operation of the Holy Spirit, Who effects the change." This view is witnessed to by the prayers of the Divine Liturgy of St. John Chrysostom, when the priest says: "Accept, O God, our supplications, make us to be worthy to offer unto thee supplications and prayers and bloodless sacrifices for all thy people," and "Remembering this saving commandment and all those things which came to pass for us: the cross, the grave, the resurrection on the third day, the ascension into heaven, the sitting down at the right hand, the second and glorious coming again, Thine own of Thine own we offer unto Thee on behalf of all and for all," and "… Thou didst become man and didst take the name of our High Priest, and deliver unto us the priestly rite of this liturgical and bloodless sacrifice…"