Mbh 5.28.1a

“Yudhishthira said, ‘Without doubt, O Sanjaya, it is true that righteous deeds are the foremost of all our acts, as thou sayest. Thou shouldst, however, ensure me having first ascertained whether it is virtue or vice that I practise. When vice assumes the aspects of virtue and virtue itself wholly seems as vice, and virtue, again, appears in its native form, they that are learned should discriminate it by means of their reason. So, again, virtue and vice, which are both eternal and absolute, exchange their aspects during seasons of distress. One should follow without deviation the duties prescribed for the order to which he belongs by birth. Know, O Sanjaya, that duties in seasons of distress are otherwise. When his means of living are totally gone, the man, that is destitute should certainly desire those other means by which he may be able to discharge the sanctioned duties of his order. One that is not destitute of his means of living, as also one that is in distress, are, O Sanjaya, both to be blamed, if they act as if the state of each were otherwise. When the Creator hath ordained expiation for those Brahmanas, who, without wishing for self-destruction, betake themselves to acts not sanctioned for them, this proves that people may, in season of distress, betake to acts not ordained for the orders to which they belong. And, O Sanjaya, thou shouldst regard them as worthy that adhere to the practices of their own order in usual times as also those that do not adhere to them in season of distress; thou shouldst censure them that act otherwise in usual times while adhering to their ordained practices during times of distress. As regards men desiring to bring their minds under control, when they endeavour to acquire a knowledge of self, the practices that are ordained for the best, viz., the Brahmanas, are equally ordained for them.