Reading Guide. Sugriva explains how his quarrel with Vali goes back to when Vali was fighting a demon (the "enemy" referred to in the story below), and Sugriva then asks for Rama's help to confront Vali in battle.
Image: The illustration below is a detail; to see the hermitage of Matanga where Sugriva has taken refuge, see the full-size view of the image.
Source. Rama and the Monkeys by Geraldine Hodgson (1903). [300 words]
Hanuman | 42. Sugriva's Story | Sugriva and Vali
Whereupon this best of monkeys told Rama how it had come to pass that Vali, his elder brother, should have behaved so badly.
It appeared that on one occasion Vali, being attacked by an enemy, pursued him in the moonlight till the creature, finding a hole, ran down it under the earth. Then Vali, leaving Sugriva with orders to guard the mouth till his return, followed his enemy into the hole, and Sugriva watched faithfully for one whole year. Then, hearing fierce cries but no sound of his brother's voice and seeing blood issue from the mouth of the cave, Sugriva believed that Vali had been killed and returned to Kishkindha and ruled his brother's subjects.
Yet as a matter of fact, Vali had not been killed and, when he had destroyed his enemy, he came back to the mouth of the hole. But as Sugriva, before leaving it, had filled it in with the top of a mountain, Vali had the greatest difficulty in getting out again, and when he once arrived back in Kishkindha, he refused to believe Sugriva's tale but declared that his younger brother had filled up the hole of the cavern with a mountain top to keep him a prisoner and so to get safe possession of his kingdom.
Nothing that Sugriva could say or do could assuage his anger, and Vali took away Sugriva's wife and turned that best of monkeys adrift with nothing on but a single cloth.
"So, Rama, has it come about," said Sugriva in conclusion of his story, "that I am alone here with Hanuman and his followers. All my defense is in these faithful apes who accompany me always."
On hearing this pitiful tale Rama prepared at once to avenge his friend Sugriva and, having given that best of monkeys unmistakable proof of his great strength, he begged Sugriva to challenge Vali to meet them in battle.
Hanuman | Sugriva's Story | Sugriva and Vali