Rekha
When Sita asks Rama to fetch the magical, golden deer for her, Rama asks Lakshmana to guard Sita and their home, and to take special care since he felt bad omens and sensed danger and evil. The golden deer is in fact the demon Maricha, who must distract Rama and Lakshmana away from the hut so as to allow Ravana to kidnap Sita.
When Rama kills the deer, even as he is dying, Maricha cries out in Rama's own voice, crying for Sita and Lakshmana to help him. Although Lakshmana knows that Rama is invincible and beyond any danger, Sita panics and frantically orders Lakshmana to go to Rama's aid immediately. Unable to disobey the frightened and panicky Sita, and genuinely beginning to fear for Rama's safety, Lakshmana goes out to search for him. He however uses his mystical power to draw the Lakshmana Rekha or Lakshmana's Limit, a perimeter line across the hut that Sita must not cross, and no other being save Lakshmana or Rama may enter uninvited. If any intruder enters, it will be instantly killed.
Sita however, out of compulsion of religious duty and compassion for a poor brahmin, who is actually the disguised Ravana, crosses the line to give him alms. Thus Ravana was safely able to seize Sita.
The Lakshmana Rekha has become a metaphor in situations where a certain limit must not be transgressed by human beings in any circumstance whatsoever.
Ramacharitamanas, the wildly popular North Indian rendering of story of Rama, does not feature the Lakshmana Rekha story in the Aranya Kanda. Neither does the original, the Valmiki Ramayana. However in Lanka Kanda of the Ramcharitmanas, (35.1) Mandodari rebukes Ravana on his boisterous claims of valour by hinting that his claim of strength and valour is shallow for he could not even cross a small line drawn by Shri Rama's younger brother Lakshmana.
Durvasa, Rama, and Lakshmana In the Uttara Kanda of Valmiki's Ramayana, Durvasa appears at Rama's doorstep, and seeing Lakshmana guarding the door, demands an audience with Rama. At the time, Rama was having a private conversation with Death disguised as an ascetic. Before the conversation began, Death gave Rama strict instructions that their dialogue was to remain confidential, and anyone who entered the room and saw or heard them was to be executed. Rama agreed and entrusted Lakshmana with the duty of guarding his door and fulfilling his promise to Death. Thus, when Durvasa made his demand, Lakshmana politely asked the sage to wait until Rama had finished his meeting. The sage grew angry and threatened to curse all of Ayodhya if Lakshmana did not immediately inform Rama of his arrival. Lakshmana, in a dilemma, decided it would be better that he alone die to save all of Ayodhya from falling under Durvasa's curse, and so interrupted Rama's meeting to inform him of the sage's arrival. Rama quickly concluded his meeting with Death and received the sage with due courtesy. Durvasa told Rama of his desire to be fed, and Rama fulfilled his guest's request, whereupon the satisfied sage went on his way. Rama was overcome with sorrow, for he did not want to kill his beloved brother, Lakshmana. Still, he had given his word to Death and could not go back on it. He called his advisers to help him resolve this quandary. On Vasishta's advice, he ordered Lakshmana to leave him for good, since such abandonment was equivalent to death as far as the pious were concerned. Lakshmana then went to the banks of the Sarayu, resolved on giving up the world through Yoga. Unseen by anyone, Indra took him to heaven
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