Mbh 8.69.2b

This vow, O Partha, was adopted by thee before from foolishness. In consequence of that vow thou art now, from folly, desirous of perpetrating a sinful act. Why, O Partha, dost thou rush towards thy reverend superior for slaying him, without having resolved the exceedingly subtle course of morality that is, again, difficult of being understood? I will now tell thee, O son of Pandu, this mystery connected with morality, this mystery that was declared by Bhishma, by the righteous Yudhishthira, by Vidura otherwise called Kshatri, and by Kunti, of great celebrity. I will tell thee that mystery in all its details. Listen to it, O Dhananjaya! One who speaks truth is righteous. There is nothing higher than truth. Behold, however, truth as practised is exceedingly difficult to be understood as regards its essential attributes. Truth may be unutterable, and even falsehood may be utterable where falsehood would become truth and truth would become falsehood. In a situation of peril to life and in marriage, falsehood becomes utterable. In a situation involving the loss of one's entire property, falsehood becomes utterable. On an occasion of marriage, or of enjoying a woman, or when life is in danger, or when one's entire property is about to be taken away, or for the sake of a Brahmana, falsehood may be uttered. These five kinds of falsehood have been declared to be sinless. On these occasions falsehood would become truth and truth would become falsehood. He is a fool that practises truth without knowing the difference between truth and falsehood. One is said to be conversant with morality when one is able to distinguish between truth and falsehood. What wonder then in this that a man of wisdom, by perpetrating even a cruel act, may obtain great merit like Valaka by the slaughter of the blind beast? What wonder, again, in this that a foolish and ignorant person, from even the desire of winning merit, earns great sin like Kausika (living) among the rivers?"