The altar is the central focus of a Catholic church. In the Rite of Dedication of a Church and an Altar, all the blessing begins at the altar and spreads out from there. After sprinkling the altar, the bishop sprinkles the people and the walls of the church. After anointing the altar, he anoints the walls. After incensing the altar, he incenses the people. After lighting the altar, he lights candles on the walls. In other words, Christ begins at the altar and emanates outward from there.
Some people think that what makes a church Catholic is the tabernacle. No, it is the altar. For the first millennium, Catholic churches rarely had tabernacles, and when they did, they were cupboards in the sacristy, out of the sight of most people. Even in modern times, in Europe, the reserved Eucharist was kept in a separate chapel.
The altar is a place of action. Gathered around the altar, we do the fourfold action of the Eucharist: we take, bless, break, and eat. This follows the fourfold action of Jesus at the Last Supper. He took bread, blessed it, broke it, and said: “Take and eat.” Eucharist is more a verb than a noun. Catholics have often been guilty of making Eucharist into a noun: the consecrated bread and wine, the Real Presence. While this is true, it is secondary to the action.
Likewise, Catholics will often tell you that the high point of the Mass is Communion. No, the high point of the Mass is the Eucharistic Prayer. That is the time when we join ourselves to the action of Christ. We become one with his self-offering. We offer our lives. Listen to the prayer: “May he make of us an eternal offering to you.” We pray that “filled with his Holy Spirit, [we] may become one body, one spirit in Christ.”
St. Augustine said, “The altar is Christ.” He did not mean that the stone was sacred. He meant that the self-offering surrounding it and laid on it was sacred: the Body of Christ in the bread and wine and the Body of Christ, the Church, who laid it there.
~ Fr. Frank Coady