According to Catholic Online:
The most likely origin is that it derived from the Lucernarium, the evening office with which early Christians began the vigil for every Sunday and especially that of Easter. In turn, this rite is probably inspired by the Jewish custom of lighting a lamp at the conclusion of the Sabbath. The rite therefore has its roots in the very beginning of Christianity. In the Lucernarium rite the light destined to dispel the darkness of night was offered to Christ as the splendor of the Father and indefectible light. This Sunday rite was logically carried out with greater solemnity during the Easter Vigil.Ah...back to our very roots in the Jewish custom celebrated, no doubt, by Joseph and Mary in their little home in Nazareth. Think of the fascination children have for candles and flickering flames
and imagine the toddler Jesus wide-eyed and spellbound on Mary's lamp as she lit the candle.
The solemn use of the candle dates at the very latest to the second half of the 4th century uniting us to all those holy men and women who went before us. So many saints I invoke share with me that beautiful rite of witnessing the Easter fire and lighting the paschal candle. When I think of St. Therese praying in her cloister, St. Thomas More in his parish at Chelsea, St. Maximilian Kolbe in the squalid barracks of Auschwitz, St. Catherine of Siena dictating letters to Pope Urban VI, St. Joan of Arc leading the army of France, St. Dominic preaching to Albigensian heretics, the little children of Fatima attending Mass with their families...all share with me the experience of seeing the paschal candle to dispel the darkness of sin and welcome Christ Our Light.
How I love our Catholic faith that gives us so many rich traditionss that stir our hearts through the use of our senses. We are a people who need our faith with skin on. "Rejoice in the Lord always....Taste and see how good the Lord is!!"