What is Transsubstantiation

At the center of the Catholic mass is the celebration of the Eucharist, or the breaking and partaking of bread and wine in community to remember Jesus’ death and resurrection. Catholic theology teaches that through the priest’s words of consecration, the conversion of the substance of the Eucharistic elements become the body and blood of Christ., although, the appearances of bread and wine remain the same.

The Altar and Tabernacle

The Eucharist is celebrated on a special table, known as the altar. The table functions as both an altar of sacrifice and a banquet table for the Eucharist, quoting St. Thomas Aquinas, says is both "a memorial of Christ's death and resurrection" and "a paschal banquet — in which Christ is eaten, the heart is filled with grace, and a pledge of future glory given to us." The bread and wine, once consecrated, remain fundamentally the holy body and blood of Christ. Any unconsumed bread or wine must either be consumed after the mass or stored in a metal box known as the tabernacle, historically on the altar.  The red votive candle, known as the sanctuary lamp, is traditionally lit beside the tabernacle to show that it contains the consecrated elements. The sanctuary lamp reminds Catholics that Jesus is present in the tabernacle, and churchgoers often pray before the tabernacle and reflect on the mystery of Christ’s presence in the Eucharist.

What Do the Candles Signify

Candles play an important and historic part of the Catholic mass, and are found in areas of the church dedicated to both reflection and gathering.  The presence of candles has long been both practical (as a source of light) and symbolic as to the importance of the mass.

How many candles are used is based upon the occasion. A “Low Mass” (without singing) ordinary mass during the weekday there may be two candles lit A “High Mass” (with almost all the audible parts of the Mass being sung) of a holy day there are to be six candles burning. One additional candle may be lit for a Bishop attending the mass.

Catholics light candles as a reminder that their prayers continue to rise to God even after they leave the church building. Candles also symbolize the rising of believers’ prayers to God, and remind Catholics that Jesus is the church’s light and that they are called to be God’s light to others

To understand the functions of the  candle on the altar of a Catholic church, it helps to understand some of the theology of the mass.