The blessing of the “paschal candle”, which is a column of wax of exceptional size, usually fixed in a great candlestick specially destined for that purpose, is a notable feature of the service on Holy Saturday. The blessing is performed by the deacon or priest, wearing a white dalmatic. A long Eucharistic prayer, the “Præconium paschali” or “Exultet”, is chanted by him, and in the course of this chanting the candle is first ornamented with five grains of incense and then lighted with the newly blessed fire. At a later stage in the service, during the blessing of the font, the same candle is plunged three times into the water with the words: Descendat in hanc plenitudinem fontis virtus Spiritus Sancti” (May the power of the Holy Spirit come down into the fulness of this fountain). From Holy Saturday until Ascension Day the paschal candle is left with its candlestick in the sanctuary, standing upon the Gospel side of the altar, and it is lighted during high Mass and solemn Vespers on Sundays. It is extinguished after the Gospel on Ascension Day and is then removed.

– From the Catholic Encyclopedia

Signficance
The candle symbolizes Jesus Christ, whom Christians regard as “the light of the world.” The light from candles represents the glory of Christ’s resurrection from the dead, which dispelled the darkness of death.

Easter
During the 50 days following Easter, the paschal candle stands in the sanctuary where it is lit at every Mass and at morning and evening prayers.

Baptism
The lit paschal candle stands beside the baptismal font. At the end of the ceremony, the priest or deacon takes a small candle, lights it from the paschal candle and presents it to the godfather, symbolizing that the newly baptized person has received the light of Christ.

Funeral
During a funeral Mass, the lit paschal candle stands at the head of the casket, reminding the mourners that the deceased will have a share in Christ’s resurrection.