When the mind accepts impure to be impure,we become pure

Impurity is essentially a perception-distorter. The impurity of addiction to alcohol makes alcoholics think that the alcohol which is the cause of their suffering is the source of irresistible pleasure.

Similarly, when we have the impurity of, say, greed, it makes getting money by any means, ethical or unethical, seem attractive. For the soul capable of relishing pure eternal love for Krishna, obsession with temporary worldly things is an impurity. All such impurities deprive us of the unlimited joy of absorption in Krishna and sentence us to the misery of pursuing petty things – a pursuit that brings a lot of karmic entanglement and misery with at best only a little enjoyment.

As long as the mind is under the spell of greed, it keeps propositioning us to possess and enjoy material things. 

Studying scripture helps us understand intellectually why impurities are impurities. But still the mind doesn’t accept it. As long as it is under the spell of greed, it continues to see worldly things as enjoyable and keeps propositioning us to possess and enjoy them. Of course, we can and should use our intelligence to say no to the mind’s schemes. But as long as the mind keeps making such proposals, we can understand that we are still impure.

Nonetheless, if we keep practicing bhakti-yoga steadily and sincerely, the repeated exposure to Krishna and the deep spiritual fulfillment thereof will gradually persuade the mind that real happiness lies in him alone – and that impure indulgences bring not enjoyment but entanglement and misery.

When the mind thus accepts the impure to be impure and gives up the desire to enjoy, it becomes peaceful. And we become joyful in our practice of devotion, for we no longer have to undergo the inner struggle with temptation that interferes with the joy of devotion. The Bhagavad-gita (06.27) declares that those with such a peaceful and pure mind relish the supreme bliss.