From the wheels to the armor, every part of the chariot has gone into its place. Until now Rama has given the chariot no name. He has only been counting its parts, and Vibhishana has been fitting them together as he listened. Now Rama draws the whole frame into a single sentence and gives it the name by which this episode has been known for centuries.
Friend, whoever holds a chariot made of dharma like this has no enemy anywhere left to conquer. Made of dharma: every part that was counted, from valor at the bottom to reverence for the guru at the top, joins into one chariot, and the name of that chariot is dharma. Listen to how the sentence moves. It goes past saying that the owner of such a chariot defeats every enemy. It says that for him no enemy remains to be conquered at all, in any place. Before a chariot made of dharma an enemy does not stand. Ravana’s name appears nowhere in the line, and Vibhishana’s question has been answered in full by it.
One more thing lies quietly inside the sentence. Rama’s own name is nowhere in the line. He says, whoever holds such a chariot. Vibhishana had asked his question out of fear for Rama’s safety, and in answer Rama hands him a chariot that anyone can build for himself, Vibhishana included. Here the direction of the teaching turns, away from Rama standing on the field and toward the listener, who until now had only been afraid.
And still Rama does not stop. A doha is the couplet that closes a run of chaupais, the place where Tulsidas gathers what the lines before it have built and sets it down with a weight of its own. What the chaupai has said, the doha now lifts one height higher.
Listen, friend of steady mind: the warrior whose chariot is firm like this can conquer even that great unconquerable enemy, the world itself. The world here means the wheel of birth and death. The enemy Tulsidas names in this line was visible to no one on that field, and every warrior standing there was under its rule: Ravana, every champion in his army, and the bears and monkeys who had come running that day with hills in their arms. The power that brings death after every birth and birth after every death has never been defeated by an arrow. That is what makes it the great unconquerable one. Rama says that the warrior whose chariot of dharma is firm can defeat even this. The commentary opens what the line leaves folded inside it: what, then, is Ravana? Against a chariot that can conquer birth and death, a single rakshasa seated on a war chariot no longer needs to be measured.
Stay a moment on the word firm. In the chaupai Rama said only a chariot made of dharma; in the doha he adds that it must be firm. To be built is one thing; to stay whole through the shocks of a battle is another. Wheels, cords, quiver, armor, each part must be of a kind that does not come loose at the first blow, and the joints between them must hold as surely as the parts themselves. For a fight against an enemy like birth and death, Rama asks for a chariot of exactly that kind.
And then the address. The man Tulsidas had called adhira a few lines earlier, unsteadied, Rama now calls matidhira, the one whose mind is steady. Vibhishana has changed nothing in himself yet. He has only listened. But Rama calls the one who has heard this chariot described to its end by the very name that belongs to one of its wheels. The teaching closes on the word whose absence began it. With that address Rama’s speech is complete, and the turn to speak passes to Vibhishana.
Source: Tulsidas, Ramcharitmanas, Lankakanda