buddhiḥ sā pārtha rājasī

yaya-by which; dharmam-principles of religion; adharmam ca-and irreligion; karyam-work; ca-also; akaryam-what ought not to be done; eva-certainly; ca-also; ayathavat-not perfectly; prajanati-knows; buddhih-intelligence; sa-that; partha-O son of Prtha; rajasi-in the mode of passion.