This sentence provides us with a bit of fire imagery that begins with a glow, is eventually kindled, and erupts in to a fire, one that provides the fuel for Steven's smithy to produce this poem (and in turn conscience?) This sentence is noteworthy for the way it can connect into the novel's second to last sentence, but its also worth remembering Father Arnall's Hell sermon that once filled Steven with such dread. Once a scared boy, Steven now embraces the element deriving positive emotions from it and using it as inspiration for his art as well. This further drives home the idea that Steven has reshaped his world and moved away from his inherited fears that inhibited his progress as an artist, but also suggests that these ideologies are still within him somewhere, perhaps not influencing his actions, but always shaping perspective.