Burning the equipment of the old life is what turns an intention into a decision the body obeys.
A call that leaves a man's plough in working order gets renegotiated on every hard morning. While the oxen still pull, the mind runs a return plan in the background, and that second plan splits the state; a split state leaks into hedging, hedging produces half effort, and half effort never compounds into a prophet.
Feeding the village with that fire makes the commitment witnessed, and witnessed commitments are harder to quietly reverse. Following Elijah afterward is the proof of a choice the fire had already closed. The cost is losing the reassurance that the old field still waits, and that reassurance was funding years of delay.