What is the X in X-mas?
(Greek: "invocation"), in the Christian eucharistic prayer (anaphora), the special invocation of the Holy Spirit; in most Eastern Christian liturgies it follows the words of institution-the words used, according to the New Testament, by Jesus himself at the Last Supper-"This is my body . . . this is my blood" and has a clearly consecratory character. The epiclesis specifically asks that bread and wine be made the body and blood of Christ, and the actual change (Greek: metabole) is attributed to the Holy Spirit. It reflects the prevailing sacramental theology of the Eastern Church, which interprets the effectiveness of the sacraments as an answer of God to the prayer of the church rather than as a result of the vicarious powers of a priest pronouncing the appropriate formula. The epiclesis also maintains the trinitarian character of the eucharistic prayer, which is addressed to the Father, commemorates the saving action of the Son, and invokes the power of the Spirit