The Jataka, Vol. II, tr. by W.H.D. Rouse, , at sacred-texts.com
"Who rashly undertakes," etc.--This story the Master told while staying in his gabled chamber, about a barber who lived at Vesāli.
This man, as we are told, used to do shaving and hairdressing and cross-plaiting for the royal household, kings and queens, princes and princesses, indeed he did all of that kind that had to be done. He was a true believer, sheltered in the Three Refuges 1, resolved to keep the Five Precepts; and from time to time he would listen to the Master's discoursing.
One day he set out to do his work in the palace, taking his son with him. The young fellow, seeing a Licchavi girl drest up fine and grand, like a nymph, fell in love for desire of her. He said to his father, as they left the palace in company, "There is a girl--if I get her, I shall live; but if I don't, there's nothing but death for me." He would not touch a morsel of food, but lay down hugging the bedstead. His father found him and said, "Why, son, don't set your mind on forbidden fruit. You are a nobody--a barber's son; this Licchavi girl is a highborn lady. You're no match for her. I'll find you somebody else; a girl of your own place and station." But the lad would not listen to him. Then came mother, brother, and sister, aunt and uncle, all his kinsfolk, and all his friends and companions, trying to pacify him; but pacify him they could not. So he pined and pined away, and lay there until he died.
Then the father performed his obsequies, and did what is usual to do for the spirits of the dead.  By and by, when the first edge of grief had worn off, he thought he would wait upon the Master. Taking a large present of flowers, scents, and perfumes, he repaired to Mahāvana, and did reverence to the Master, saluted him, and sat down on one side. "Why have you kept out of sight all this time, layman?" the Master asked. Then the man told him what had happened. Said the Master, "Ah, layman, ’tis not the first time he has perished by setting his heart on what he must not have; this is only what he has done before." Then at the layman's request, he told a story of the olden time.
Once upon a time, while Brahmadatta was king of Benares, the Bodhisatta came into the world as a young Lion in the region of Himalaya. Of the same family there were some younger brothers, and one sister; and all of them lived in a Golden Cave.
Now hard by this cave was a Cave of Crystal on a silver hill, where a Jackal lived. By and by the Lions lost their parents by the stroke of death. Then they used to leave the Lioness, their sister, behind in the cave, while they ranged for food; which when they obtained, they would bring it back for her to eat.
Now the Jackal had caught sight of this Lioness, and fell in love with her; but while the old Lion and Lioness lived, he could win no access. Now, when the seven brothers went to seek food, out he came from his Crystal Cave, and made all haste to the Golden Cave; where, taking his stand before the young Lioness, he addressed her slily with these seductive and tempting words:
"O Lioness, I am a fourfoot creature, and so are you. Therefore do you be my mate, and I will be your husband! We will live together in friendship and amity, and you shall love me always!"
Now on hearing this the Lioness thought to herself, "This Jackal here is mean amongst beasts, vile, and like a man of low caste: but I am esteemed to be one of royal issue. That he to me should so speak is unseemly and evil. How can I live after hearing such things said? I will hold my breath until I shall die."--Then, bethinking her awhile, "Nay," quoth she, "to die so would not be comely. My brothers will soon be home again; I will  tell them first, and then I will put an end to myself."
The Jackal, finding that no answer came, felt sure she cared nothing for him; so back he went to his Crystal Cave, and lay down in much misery.
Now one of the young Lions, having killed a buffalo, or an elephant, or what not, himself ate some of it, and brought back a share for his sister, which he gave her, inviting her to eat. "No, brother," says she, "not a bite will I eat; for I must die!" "Why must that be?" he asked. And she told him what had happened. "Where is this Jackal now?" he asked. She saw him lying in the Crystal Cave, and thinking he was up in the sky 1, she said, "Why, brother, cannot you see him there on Silver Mountain, lying up in the sky?" The young Lion, unaware that the Jackal lay in a Crystal Cave, and deeming that he was truly in the sky, made a spring, as lions do, to kill him, and struck against the crystal: which burst his heart asunder, and falling to the foot of the mountain, he perished straightway.
Then came in another, to whom the Lioness told the same tale. This Lion did even as the first, and fell dead by the mountain foot.
When six of the brother Lions had perished in this way, last of all entered the Bodhisatta. When she had told her story, he enquired where was the Jackal now? "There he is," said she, "up in the sky, above Silver Mountain!" The Bodhisatta thought--"Jackals lying in the sky? nonsense. I know what it is: he is lying in a Crystal Cave." So he repaired to the mountain's foot, and there he saw his six brothers lying dead. "I see how it is," thought he; "these were all foolish, and lacked the fulness of wisdom; not knowing that this is the Crystal Cave, they beat their hearts out against it, and were killed. This is what comes of acting in rashness without due reflection;" and he repeated the first stanza:--
 After repeating these lines, the Lion continued: "My brothers wanted to kill this Jackal, but knew not how to lay their plans cleverly; so they leapt up too quickly at him, and so came by their death. This I will not do; but I will make the Jackal burst his own heart as he lies there in the Crystal Cave." So he espied out the path whereby the Jackal used to go up and down, and turning that way he roared thrice the lions roar, that earth and heaven together were all one great roaring! The Jackal lying in the Crystal Cave was frightened and astounded, so that his heart burst; and he perished on the spot incontinently.
The Master continued, "Thus did this Jackal perish on hearing the Lion roar." And becoming perfectly enlightened, he repeated the second stanza:--
 Thus did our Lion do this Jackal to death. Then he laid his brothers together in one grave, and told the sister they were dead, and comforted her; and he lived the rest of his days in the Golden Cave, until he passed away to the place which his merits had earned for him.
When the Master had ended this discourse, he revealed the Truths, and identified the Birth:--at the conclusion of the Truths, the layman was established in the Fruit of the First Path:--"The barber's son of to-day was then the Jackal; the Licchavi girl was the young Lioness; the six younger Lions are now six Elders; and I myself am the eldest Lion."
4:1 Buddha, the Law, and the Order of Brethren.
5:1 i.e. because of the transparency.