https://www.gradesaver.com/the-road/q-and-a/as-the-father-is-dying-he-tells-his-son-he-must-go-on-in-order-to-carry-the-fire-when-the-boy-asks-if-the-fire-is-real-the-father-says--its-inside-you-it-was-always-there-i-can-see-it-whst-is-this-fire-why-is-it-so-crucial-that-they-not-let-i-303375
It's on here, but to summarize:
The boy is positive and good in a negative world. Representing the boy's goodness, the fire shows how he's virtuous and helpful despite hardship.
