The answer lies in Germanic customs, my friend. The candle is an adaptation of the Yule Log. In Scandinavia in particular, this time of year has only wan light for about 5 hours and total darkness the rest of the time. Further north, around Trondheim in Norway, it is completely dark. The Yule fires were to burn through the night to keep people safe from the monsters that roam at night, from the biting cold, and should it burn through the night without going out, it would bring good luck through the coming year.

Some see it as a portion of the sun's light (the sun, btw, is female for us as it is with the Celts) and I have to say that in some small way I hold to this as well. By burning through the night, it casts away shadows and drives away those malicious spirits that would do us harm at a time when they are at their most powerful. In that, the fires are protective and a small portion of Sunna's blessing for us when it is coldest and darkest.

While today we know the sun will rise again because we understand far more than our ancestors, they did not know for sure it would. The fires were a way to guide the sun back to us so that we may enjoy Sunna's radiance again.