Ravana's guards, while he was in Lanka, had succeeded in catching Hanuman, who was then brought to the demon-king's court. At Ravana's command his tail was set on fire and with his burning tail Hanuman created a great havoc in Lanka. When Rama's younger brother was lying unconscious in the battlefield and the herb that could cure him was not available, he came forward to bring that herb from Himalayas. In the hurry when Hanuman could not trace that magical herb he lifted the complete hill and flew to bring the same to battlefield. The arrow that had wounded Lakshmana was blessed in the way that whoever was wounded in the night with it could not recover if the cure was not obtained before daylight.
Hanuman knew this and was determined to bring it before the sun rose. The powerful Ravana compelled the sun to arise on the mountain at midnight. Hanuman being enraged at this conspiracy, leaped up and seizing sun's chariot placed the blazing god under his arm and put the mountain on his head. Only after the application of the desired herb on the wound of Lakshmana, Hanuman permitted the sun to depart.
Hanuman accompanied Rama on his return to Ayodhya and Rama gave him the blessings of perpetual youth and deathless existence. He was so intensely devoted to Rama and Sita that once he even tore up his chest with claws and showed that images of Rama and Sita were in his heart.
Shree Hanuman is believed to have received a boon from Shri Ram to become immortal for His sheer acts of worship and it is said that Shri Hanuman is always at an arm's length for anyone who seeks Him with the truest faith and sincere belief. Hanuman has always been associated with protection and welfare of our health especially for children and His legendary life-saving act of carrying the mountain that contained the miraculous herb Sanjivani that cured Lakshman is remembered even today.