Who promised Arjuna of stabalizing and strengthening his Chariot in the Kurukshetra war?

Hanuman promised to stabilize and strengthen Arjuna's chariot during the Kurukshetra war. He appeared on Arjuna's flag (dwijah) and protected his chariot from the powerful weapons of the enemy. This blessing was sought by Arjuna through Krishna's advice and helped ensure his chariot remained stable despite devastating attacks.