Mahabharata Sauptika Parva Chapter 15:2

Mahabharata Sauptika Parva Chapter 15:2 For this reason, the mighty-armed son of Pandu, although he had the power, would not, from desire of doing good to living creatures, baffle thy weapon with his. The Pandavas should be protected; thy own self should be protected; the kingdom also should be protected. Therefore, O thou of mighty arms, withdraw this celestial weapon of thine. Dispel this wrath from thy heart and let the Pandavas be safe. The royal sage Yudhishthira never desires to win victory by perpetrating any sinful act. Give unto these that gem which is on thy head. Taking that, the Pandavas will in return grant thee thy life!' "Drona's son said, 'This my gem is more valuable than all the wealth that has ever been earned by the Pandavas and the Kauravas. If this gem is worn, the wearer ceases to have any fear from weapons or disease or hunger! He ceases to have any fear of gods and Danavas and Nagas! His apprehensions from Rakshasas as also from robbers will cease. Even these are the virtues of this gem of mine. I cannot, by any means, part with it. That, however, O holy one, which thou sayest, should be done by me. Here is this gem. Here is myself. This blade of grass (inspired into a fatal weapon) will, however, fall into the wombs of the Pandava women, for this weapon is high and mighty, and incapable of being frustrated. O regenerate one, I am unable to withdraw it, having once let it off. I will now throw this weapon into the wombs of the Pandava women. As regards thy commands in other respects, O holy one, I shall certainly obey them.' "Vyasa said, 'Do then this. Do not, however, entertain any other purpose, O sinless one! Throwing this weapon into the wombs of the Pandava women, stop thyself.'"Vaishampayana continued, "The son of Drona, having heard these words of the island-born, threw that uplifted weapon into the wombs of the Pandava women."