The four candles on an Advent wreath represent the 4,000 years between Adam and Eve and the birth of Christ during which mankind waited for the arrival of Jesus. A candle on the wreath is lit each Sunday during the season of Advent to signify the entrance of Christ, the light, into the world.
There are three purple candles and one rose-colored candle on an Advent wreath. The purple candles are lit over the course of the first two and fourth Sundays of Advent. These candles represent prayer, penance and preparation for the coming of the Lord that each person is expected to undertake during the Advent season. The rose candle is lit on the third Sunday, Gaudete Sunday, and it represents joy. Gaudete Sunday is seen as a day of rejoicing because it marks the midpoint of Advent.
A white candle can also be placed in the middle of the Advent wreath. When used, this candle is often called the Christ candle. It is only lit on Christmas and represents the birth and purity of the Christ child. The candles are lit progressively throughout Advent to show the hope and expectation of the first coming of Christ and the anticipation of the second coming where Jesus is to judge the living and dead.