In the Bhagavata, Sankaradeva Says: -
"If acts are done with sinful motive, no virtue results. In this dire Iron age evil - intentioned people have no competence for any act whatsoever. Just as neither earth nor plenty of water can purify gold but only repeated heating of it on the fire can do purifying; so by practicing penance, mutterings, sacrifices and yogic exercises trouble is counted in vain, since the knot of action is not severed unless God is enshrined in the heart.
Let me tell you this truth: the heart cannot be purified by worshipping gods, by practicing yoga, by taking ablution in all sacred waters, nor by donation, fasting and penance. I cite you, Oh Parikshit, this essence of the scrip tures: in Iron Age no rescue
is there like purifying the mind by harboring the God of the world in the heart."3