The Jataka, Volume I, tr. by Robert Chalmers, , at sacred-texts.com
"He bolts the die."--This story was told by the Master while at Jetavana, about using things thoughtlessly.
Tradition says that most of the Brethren of that day were in the habit of using robes and so forth, which were given them, in a thoughtless manner. And their thoughtless use of the Four Requisites as a rule barred their escape from the doom of re-birth in hell and the animal world. Knowing this, the Master set forth the lessons of virtue and showed the danger of such thoughtless use of things, exhorting them to be careful in the use of the Four Requisites, and laying down this rule, "The thoughtful Brother has a definite object in view when he wears a robe, namely, to keep off the cold." After laying down similar rules for the other Requisites, he concluded by saying, "Such is the thoughtful use which should be made of the Four Requisites. Thoughtlessly to use them is like taking deadly poison; and there were those in bygone days who through their thoughtlessness did inadvertently take poison, to their exceeding hurt in due season." So saying he told this story of the past.
Once on a time when Brahmadatta was reigning in Benares, the Bodhisatta was born into a well-to-do family, and when he grew up, he became a dice-player. With him used to play a sharper, who kept on playing while he was winning, but, when luck turned, broke up the game by putting one of the dice in his mouth and pretending it was lost,--after which he would take himself off.  "Very good," said the Bodhisatta
when he realised what was being done; "we'll look into this." So he took some dice, anointed them at home with poison, dried them carefully, and then carried them with him to the sharper, whom he challenged to a game. The other was willing, the dice-board was got ready, and play began. No sooner did the sharper begin to lose than he popped one of the dice into his mouth. Observing him in the act, the Bodhisatta remarked, "Swallow away; you will not fail to find out what it really is in a little time." And he uttered this stanza of rebuke:--
[paragraph continues] But while the Bodhisatta was talking away, the poison began to work on the sharper; he grew faint, rolled his eyes, and bending double with pain fell to the ground. "Now," said the Bodhisatta, "I must save the rascal's life." So he mixed some simples and administered an emetic until vomiting ensued. Then he administered a draught of ghee with honey and sugar and other ingredients, and by this means made the fellow all right again. Then he exhorted him not to do such a thing again. After a life spent in charity and other good works, the Bodhisatta passed away to fare thereafter according to his deserts.
His lesson ended, the Master said, "Brethren, the thoughtless use of things is like the thoughtless taking of deadly poison." So saying, he identified the Birth in these words, "I was myself the wise and good gambler of those days."
(Pāli Note. "No mention is made of the sharper,--the reason being that, here as elsewhere, no mention is made of persons who are not spoken of at this date.")