अयथावत्प्रजानाति बुद्धि: सा पार्थ राजसी ॥ ३१ ॥
kāryaṁ cākāryam eva ca
buddhiḥ sā pārtha rājasī
yayā — by which; dharmam — the principles of religion; adharmam — irreligion; ca — and; kāryam — what ought to be done; ca — also; akāryam — what ought not to be done; eva — certainly; ca — also; ayathā-vat — imperfectly; prajānāti — knows; buddhiḥ — intelligence; sā — that; pārtha — O son of Pṛthā; rājasī — in the mode of passion.
O son of Pṛthā, that understanding which cannot distinguish between religion and irreligion, between action that should be done and action that should not be done, is in the mode of passion.