I find a fascinating aspect of this prayer is the epiclesis (“invocation).  I have most often thought of this word as referring to asking the Holy Spirit to come down and do something, as when we invoke the Holy Spirit on the waters for Baptism or upon the person to be ordained a priest.  But the word is a bit broader in our Mass.  It is invoking God and divine power in general to achieve a change in the bread and wine into the Body and Blood of the Lord.

The gesture accompanying the prayer is the priest bringing his hands down over the gifts.  Thus, visually, we all can see what we are praying.

In the First Eucharistic Prayer, the old Roman Canon, there is no explicit invoking of the Holy Spirit.  Rather, just before the consecration of the bread and wine, the priest invokes God that these gifts become the Body and Blood of the Lord and imposes his hands over the gifts. 

In the other Eucharistic Prayers, written after the Second Vatican Council, an explicit mention of the Holy Spirit is included at this point.  It is thought that this calling on the Holy Spirit by name is brought into our prayers from the Eucharistic Prayers of the Eastern Churches which already mentioned the role of the Holy Spirit for many centuries.

The Eucharistic Prayer is addressed to the Father since we are offering Jesus’ own sacrifice of himself to the Father.  Perhaps, that is why in the Latin Church (the Roman Canon) the invocation is more generic, asking God to make this change, so as not to redirect our attention to another person of the Blessed Trinity.  Of course, God includes Father, Son, and Holy Spirit.

Nonetheless, it seems enriching for us to mention explicitly the role of the Holy Spirit so that we are again caught up in the activity of the Blessed Trinity.  In addition, since we have placed ourselves on the altar along with these gifts of bread and wine, this is an occasion for us to ask the Holy Spirit to change us into Jesus himself, so that we might actually become what we will later eat, his Body and his Blood.

The Catechism (#1106) quotes the Eastern Father, St. John Damascene:

You ask how the bread becomes the Body of Christ, and the wine…the Blood of Christ.  I shall tell you: the Holy Spirit comes upon them and accomplishes what surpasses every word and thought….  Let is be enough for you to understand that it is by the holy Spirit, just as it was of the Holy Virgin and by the Holy Spirit that the Lord, through in in himself, took flesh.

In any case, any invocation is a reminder to us that what is accomplished on the altar is not our work but God’s work.  Though a priest is needed to accomplish God’s work, each priest is aware that he is a vessel for the power of God in our midst.  Our participation at this point is seeing, hearing, praying with and believing.

I find it an amazing reality that we can actually invoke God’s intervention like this and he acts each time.  This is how much he loves us that God has put us at his beck and call.  Thanks be to God.