In the play Romeo and Juliet by William Shakespeare, the playwright is sure to run the continuity of the theme of Juliet bringing light right through to the very end. The "torches" that Romeo mentions re-appear right at the very end - in the family vault of death, the tomb or sepulchre of Juliet. Here, in this dark, Gothic and cheerless place, Juliet is laid to rest. It is dim and forbidding - lit only by the light of torches along the way. All the images here are of death and decay which contrast with the way Romeo and Juliet's love burned for each other - like torches. The sun, the dawn, the "fiery-footed steeds" and the torches provide a foil for the death of love that is brought about by hate - a hate that results in the extinguishing of the light of two young lives.
In this play, Romeo often talks about Juliet in terms of lights and fires. I believe that this is meant to emphasize the pure and light (as opposed to dark and impure) nature of their love for each other.
This starts with the first time he sees her. That happens in Act I, Scene 5 when he goes to the ball at her house. The very first words that Romeo speaks about Juliet are about light: "O, she doth teach the torches to burn bright!"
The other really famous place where Romeo compares Juliet to a light or fire is in the balcony scene. When he sees her, he compares her to the sun. He says:
But soft! What light through yonder window breaks?
It is the East, and Juliet is the sun!
Arise, fair sun, and kill the envious moon,
Who is already sick and pale with grief