Over the next four weeks, we are going to look at the Eucharist and the Mass, so often called "the source and summit," or the beginning and end, of the life of the Church.

Our aim will be to explore together some of the great richness of the Eucharist and the Mass: It is rather like a diamond with many facets and colors that reflect so much, as well as being of great beauty and inestimable value. We hope to understand better what we believe, why we believe it and, for that matter, how we arrived at these beliefs.

First, we'll share a few fundamental reflections about the Eucharist and the Mass. Later, we'll explore the Eucharist as a sacred meal, as the real presence of Jesus Christ and as a true memory and sacrifice.

The Eucharist is, of course, one of the seven sacraments, so it is useful to remember exactly what the sacraments are. The Catechism of the Catholic Church calls them "signs of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us."

In other words, through the use of outward, physical signs (bread and wine, water, oil and so on), every sacrament continues the saving presence and work of Jesus Christ.

The sacraments are often called symbols: they literally "throw together" - that's what the word "symbol" means - the human and earthly on the one hand and the divine and transcendent on the other hand, or the physical signs and elements and God's love and gifts.

This is what the Eucharist is and what it does, but it also has a special characteristic compared to the other sacraments: There is a unique and special presence of Jesus Christ in the Eucharist. We'll explore that later in our series.

The Eucharist and the Mass are also ancient. Like all the sacraments, they reflect and continue here and now Jesus' own ministry and mission. In fact, the roots of the Eucharist and the Mass also lie in the Old Testament.

We see this, for example, in the prayers of blessing and thanksgiving for all that God has done for us and for the good things of creation, the prayers said at the preparation of gifts or in the eucharistic prayers we use at Mass. Many understand the Eucharist as the new form of the Jewish Passover, and it is a living memorial of the Last Supper that Jesus celebrated with His disciples (Mark 14:22-25).

So, in the Eucharist, we remember all that God has done for us, and that this saving love is not just remembered but is actually made present - an amazing gift!

The Eucharist and the Mass are also a ritual encounter with the Lord. Why do we say a "ritual" encounter? We are, after all, ritual beings; we all have our daily rituals and habits, and if these do not happen, then the day often is not a good one! This is why the Eucharist and Mass follow a set pattern and structure: a ritual that is to lead us to a living encounter with God.

The structure and ritual is ancient. St. Justin, writing around 150 CE, gives a description of the Sunday Eucharist that is pretty much what we do today. (Read it at www.crossroadsinitiative.com/library_article/532/Sunday_Eucharist_in_the_Early_Church_St._Justin_Martyr.html.)

The Eucharist and the Mass are also dynamic and active; they are a pledge or a promise, a life-changer and a gift given to transform us, just as the bread and wine are transformed. (We will tackle "transubstantiation" in a later article!)

From our Sunday Mass and Eucharist, we are sent out having been fed, sustained and transformed, so we can share and live all these gifts in the week ahead. The Eucharist is also a promise or pledge - or, as one prayer puts it, it is the "foretaste and promise" of the future we hope for in heaven. This is why the Eucharist is given to those close to death (this is called "viaticum"): Just as the Eucharist was food for a person during their life, now it is the food to sustain them on their final journey to the new life.

This verse from a hymn about the Eucharist was written by St. Thomas Aquinas 800 years ago:

"Jesus, whom I look at, shrouded here below

I beseech you send me what I long for so;

Some day to gaze on you, face to face in light

And be blest for ever with your glory's sight."

(Father Barratt is pastor of St. Ambrose parish in Latham. He holds a doctorate in theology and was a professor at St. John's Seminary in England before coming to the U.S. in 2004. His previous series for The Evangelist on the creed won a national journalism award; read that series and another on coming back to reconciliation under Specials: Religious Education at www.evangelist.org.)

With this column, Father Barratt begins a four-part series during September on the Eucharist. In the coming weeks, he'll talk about the Eucharist as a sacred meal and as a sacrifice, and what the "real presence of Christ in the Eucharist" means. This series is geared toward Catholics who'd like to boost their understanding of the faith and to newcomers starting the journey toward joining the Church through the Rite of Christian Initiation of Adults.