From the Shiva Purana: Shiva’s Grace
Once upon a time, a huntsman, sitting on the branch of a tree, was trying to shoot down a deer. As he aimed the arrow, he unknowingly pushed some bilva leaves and water on a Shivalinga that was situated near the base of the tree. Before the arrow was fired, the deer gave its consent to become the hunter’s food but requested the hunter to spare some time so that it could meet its children at home and hand them over to someone for guardianship. The hunter allowed it after the deer vowed to return. While the hunter was waiting for his quarry to return, another deer appeared at the scene. The incident repeated itself exactly, and the hunter ended up dropping some more leaves and water on Shiva’s symbol. Surprisingly, the incident repeated itself a third time as the hunter waited for the second deer to return.
Towards the end of the night, the three deer (and their kids) appeared before the hunter to fulfill their promise. The hunter was pleased to see them. But as soon as he pulled the arrow for the fourth time (and dropped some more leaves on the Shivalinga), a change occurred in his mind. Feeling shameful of his actions, he questioned himself, “If deer can surrender themselves to fulfill my appetite, can I, born as a human, not bring beneficence in my own life?” His mind started generating compassion. What was the reason for this change in personality? It was Shiva’s wedding anniversary (Shivaratri), and the hunter had unknowingly observed it by offering Shiva leaves and water, four times over the night. And this karma, though performed unintentionally, was ample for a transformation. As soon as the hunter let the deer go unharmed, Shiva gave him a darshan.
Pleased with the new devotee, Shiva also gave the hunter a new name, Guha, along with boons for material abundance as well as eventual liberation. Above all, he blessed Guha with the friendship (and darshan) of Lord Rama in forthcoming times. The story tells us how the grace of Shiva is exemplary; the God of all does not need a reason to bestow it on a jiva.
Happy Maha Shivaratri!