18.47 श्रेयान् better, स्वधर्मः ones own duty, विगुणः (though) destitute of merits, परधर्मात् that the duty of another, स्वनुष्ठितात् (than) well performed, स्वभावनियतम् ordained by his own nature, कर्म action, कुर्वन् doing, न not, आप्नोति (he) incurs, किल्बिषम् sin.Commentary: Just as a poisonous substance does not harm the worm born in that substance, so he who does his Svadharma (the duty ordained according to his own nature) does not incur any sin.What is poison to the whole world is sweet to a worm and yet sugarcane juice that is sweet causes its death. So a mans appointed duty which frees him from bondage must, therefore, be practised however difficult it may seem to be. If you try to do the duty of another it will bring,danger. He who has no knowledge of the Self cannot remain even for a moment without doing action. (Cf.III.35)