Epiclesis

The epiclesis (also spelled epiklesis; from Ancient Greek: ἐπίκλησις "invocation" or "calling down from on high") is the part of the Anaphora (Eucharistic Prayer) by which the priest invokes the Holy Spirit (or the power of His blessing) upon the Eucharistic bread and wine in some Christian churches.

In most Eastern Christian traditions, the Epiclesis comes after the Anamnesis (remembrance of Jesus' words and deeds); in the Western Rite it usually precedes.

While in the Roman Catholic Church, the Words of Institution are considered to be the moment of Transubstantiation (when, according to religious tradition, the eucharistic elements would change from bread and wine into the actual Body and Blood of Christ), the Eastern Orthodox Churches do not hold this belief. Instead, the Epiclesis is believed to be the moment at which this change is completed. However, the actual process of change is not considered to begin at this moment, but begins with the Liturgy of Preparation—it is merely completed at the Epiclesis. This is illustrated in one of the opening prayers of the Preparatory Service used in the Liturgy of the Ethiopian Orthodox Tewahedo Church:

The Epiclesis is considered to be essential to the validity of the Sacred Mystery (sacrament), and in the 20th century, when Western Rite Orthodox parishes began to be established, it was necessary to add an Epiclesis to their Eucharistic rites, if one was not already there (for instance, those parishes which desired to use the Anglican Missal.)

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