As the Mahabharata tells it
Mahabharata, Vana Parva 146 to 150 · 2 min read
In the years of their exile the five Pandavas came high up into the Himalaya, and one day the wind blew a single flower down to Draupadi's feet. It had a thousand petals and it smelled like nothing she had smelled before.
"Bring me more of these," she said to Bhima. "I want to take them home."
Bhima picked up his club and went. He crashed up the mountain towards where the wind came from, roaring, scattering elephants and lions, pulling up trees that were in his way, and the noise of him went up and down the valleys.
On a narrow path between rocks, in a grove of banana trees, he found an old monkey asleep. It was lying right across the way, and its long tail was stretched out over the path.
Bhima roared at it. The monkey opened one eye.
"I am ill," it said. "I was sleeping comfortably. Why wake me? You seem a sensible man. Go back. There is nothing up here for a mortal."
"Get out of my way," said Bhima.
"I am too old to get up," said the monkey. "Step over me."
"I will not step over you," said Bhima. "The highest spirit lives in every creature's body. I will not step over it. If I did not know that, I would leap over you and over this whole mountain as Hanuman leapt the sea."
"Who is this Hanuman?" asked the monkey.
"My brother," said Bhima proudly, "son of the Wind, as I am, the one who crossed a hundred yojanas of sea for Rama's wife. I am his equal in strength. Now move."
"I cannot move," said the monkey mildly. "Lift my tail aside yourself, and go by."
Bhima laughed and took hold of the tail with his left hand. It did not move. He took it in both hands and set his feet and pulled, until his eyes bulged and the sweat poured off him and his whole body shook. He could not lift it an inch.
He let go and stood in front of the monkey with his head down and his hands folded.
"Forgive me," he said. "Who are you?"
"I am Hanuman," said the monkey, "your brother."
Bhima was overjoyed. He asked his brother to show him the form in which he had crossed the sea, and Hanuman grew until he filled the valley, as tall as a mountain, and as bright as the sun, so that Bhima had to shut his eyes. Then he became small again and embraced him, and Bhima's tiredness went out of him.
Hanuman told him about the four ages of the world, and how they decline, and showed him the way to the lake of flowers. When they parted he made Bhima a promise.
"When you go to war," he said, "I will be on Arjuna's banner. When you roar on the battlefield, I will roar with you, and your enemies will hear it and lose heart."