In Clerres, one of the most common prophecies regarding the advent of the Destroyer is know as the "candle prophecy". Here is the version that Bee Farseer dreamed about:
I dream it as a vine that splits into two branches. On one branch there are four candles growing. One by one they are kindled to flame, but their light does not illuminate. Instead, a crow says, ‘Here are four candles to light you to bed. Four candles lit means their child is dead. Four candles burn for the end of their ways. The Wolf and the jester have wasted their days.’ Then, on the other branch of the vine, three candles are suddenly kindled. Their light is almost blinding. And the same crow says, ‘Three flames burn brighter than the sun. Their blaze engulfs an evil done. Their angry mourning purpose gives. They do not know their child still lives.’ Then the crow suddenly has a broken candle. She drops it and I catch it. In a slow and frightening voice she says, ‘Child, light the fire. Burn the future and the past. It’s what you were born to do.’
We know, that the candles are the last four candles made by Molly that Fitz kept for sentimental purposes and that he lost one of the candles when his camp was attacked by bear. Later Bee finds the broken candle and takes it with her to Clerres where
she uses it to set the library on fire.
But I don't understand, why the prophecy says that "Four candles lit means their child is dead" - Bee could do what she done using something else (in fact, the candle was used only as a delay mechanism).
Let me clarify a bit: I'm looking for a cause-effect kind of explanation. If for example there was a prophecy "If you'd go left, you'll die" and on the "sure death" patch there is a dragon, evil witch or simply thunderstorm, then you'd be kill by a monster, spell or lightning, not a prophecy.