What symbolic act do the mourners do during the memorial service in “All the Darkness in the World"? What does this symbolize?

The mourners each go up to the altar with Jun's picture and a candle and they light their own candles from Jun's. This represents the light that Jun gave them in life. Danilo states, “Somebody once said, ‘All the darkness in the world cannot extinguish the light of a single candle’” (296).