Mbh 1.108.3

“The god of justice, thus questioned, replied, ‘O thou of ascetic wealth, a little insect was once pierced by thee on a blade of grass. Thou bearest now the consequence of the act. O Rishi, as a gift, however small, multiplieth in respect of its religious merits, so a sinful act multiplieth in respect of the woe it bringeth in its train.’ On hearing this, Ani-Mandavya asked, ‘O tell me truly when this act was committed by me. Told in reply by the god of justice that he had committed it, when a child, the Rishi said, ‘That shall not be a sin which may be done by a child up to the twelfth year of his age from birth. The scriptures shall not recognise it as sinful. The punishment thou hast inflicted on me for such a venial offence hath been disproportionate in severity. The killing of a Brahmana involves a sin that is heavier than the killing of any other living being. Thou shall, therefore, O god of justice, have to be born among men even in the Sudra order. And from this day I establish this limit in respect of the consequence of acts that an act shall not be sinful when committed by one below the age of fourteen. But when committed by one above that age, it shall be regarded as sin.’