A father gave a beautiful crucifix to his young daughter. Then he asked her, "Annie, what's the difference between the figure of Jesus on the crucifix and the Host that the priest holds up at the consecration of the Mass?"
Annie didn't hesitate a moment. "When I look at the figure on the cross I see Jesus, but He isn't there," she replied. "When I look at the Host, I don't see Jesus, but He is there."
This is the true nature of the Most Holy Eucharist in the Holy Sacrifice of the Mass. But how much do we really know about the Mass? Before we look a little deeper into the Mass, let's first look at a couple of the mechanics.
Let's look at the matter of the Mass. In case you don't recall, the matter of any sacrament is some concrete thing or action. In this case, we're talking about the bread and wine used at the altar. The bread for a valid Mass must be made of pure wheat flour and water. It can't have other ingredients such as milk, honey, sugar or eggs. In the Latin rite, it should also be unleavened — no yeast or baking powder.
The wine for a valid Mass must be natural grape wine of very high quality. It can't be strawberry, watermelon or muscadine. Many dioceses publish a list of wines their priests are authorized to use, and there are several religious orders that support their communities by making altar wine that's high-quality to be on the altar.
There's also the issue of the rituals used at Mass — the gestures and prayers used by the priest. On this front, there has been a lot of unauthorized liturgical experimentation going on in the last 50 years, and all of it is bad. Of course, any disobedience to the Church is bad, especially when that disobedience is perpetrated by priests. The abuses have ranged from beginning the custom of Communion in the hand to liturgical "dancers" at the altar. This level of "experimentation" with liturgy put a lot of people off and scandalized many souls.
The Mass is divided into two parts: the Liturgy of the Word (also called the Liturgy of the Catechumens), and the Liturgy of the Eucharist (also called the Liturgy of the Faithful). In the first part, Jesus speaks to us through the Bible. In the second part, Jesus offers Himself to the Father for our salvation.
When the Mass is said correctly — meaning without liturgical abuse — there are aspects of it that go all the way back to the early Church.
The Liturgy of the Catechumens and the two parts of the Mass have their origins from the ancient Roman persecutions.
In the days of the Roman Empire, the Church was forced into the catacombs due to persecution. The Church's leaders had to be cautious about the infiltration of spies. A common Roman belief about us Christians was that we were practicing cannibalism, which stems from a misunderstanding of our reception of the Body of Christ. So spies were paid to infiltrate our underground groups to gather evidence to that effect and turn us over to our persecutors.
Catechumens, those learning the Faith with the intention of joining the Church, were permitted to stay during the first half of the Mass. The very last thing catechumens were taught was the Holy Eucharist because we feared spies would cause the Mass to be raided by authorities who would desecrate the Eucharist.
So at the close of the Liturgy of the Catechumens, those not in full communion with the Church would be asked to leave with their catechists to continue their instruction. The hope was that, if a spy was in that group of catechumens, he would actually be converted by the time he learned about the Holy Eucharist.
After the Liturgy of the Catechumens is finished, we then witness the priest's celebration of the Liturgy of the Eucharist. (It's also called the Liturgy of the Faithful because, as stated above, the early Church only allowed members of the faithful to be present for it.) This is the point, of course, when Jesus offers Himself to the Father in a re-presentation of the sacrifice of the Cross. Then we receive Him in Holy Communion.
God isn't bound by time, space and dimension like you and I are. He knows no yesterday, today or tomorrow. Everything is happening for God in the present. You and I can recall what happened a moment ago, anticipate what will happen a moment from now, and experience the present now. For God, though, everything is in the present. That means He experiences the creation of the universe, the end of mankind and everything in between all at the same time.
Due to the divine and mystical nature of the Mass, when we attend Holy Mass we're simultaneously present in the Upper Room at the Last Supper, at the foot of the Cross while Jesus offers Himself to the Father for our sins, and present at the altar where Jesus perpetuates His sacrifice to the Father on our behalf.
If you were actually there in the Upper Room with Jesus and the Apostles, what would your demeanor have been? If you had been on Calvary at the foot of the Cross, standing next to the grief-stricken Mother of God, how would you have behaved? How much respect would you have shown in those situations? Would you have or express sorrow for your sins, or would you act and dress like you were at a company picnic? Well, you really are present for those events. That is something we should really keep in mind at every Mass.