Answer
If grime has accumulated on a mirror, if dust has gathered on it, you cannot see your own face in it — or at least not clearly. In the same way, when impurity settles upon the mind, the true image of the Atman is no longer visible in it, and the true image of the Supreme Lord cannot be seen. For this, it is necessary to remove the impurities of the mind.
To elucidate this very point, the Lord has used two specific terms at two places in the Gita: one is Bhava Samshuddhi, and the other is Sattva Samshuddhi. In the two Gita verses I have cited — 16:1 (Sattva Samshuddhi) and 17:16 (Bhava Samshuddhi) — these two expressions find their place.
Bhava Samshuddhi means removing negative emotions from the heart: jealousy, malice, greed, arrogance, delusion, vanity, envy, and so on. These sentiments must be eliminated — for the vision of the Self, for the vision of the Lord, and for liberation. No matter how much japa or tapas you perform, if these impurities of the mind are not removed, you will not attain the vision of the Lord. For this, you must first identify the negative emotions that exist within you. Not all negative emotions are dominant in every person — typically only two or four are prominent. For instance, one person may have an excess of anger. Another person may have no anger but an excess of greed. Yet another may have neither anger nor greed but may harbor jealousy and malice.
So each person must first identify which negative trait is strongest in him or her. Then one must consciously strive to purify that trait.
In this manner, when all the emotions have been purified, your inner being — your Sattva — also becomes completely purified. This is what is called Sattva Samshuddhi. Sattva here means the inner being, the essential inner self. You also know it by the term "character."
So when the various negative emotions of the mind have been purified, your character too is purified.
Now, the question remains: how does one purify one's emotions and character?
There are several methods. One prescribed method is the daily study of noble scriptures — such as the Gita, along with the Ramcharitmanas and the Bhagavat Purana. In the Ramcharitmanas, there are certain remarks in some places about Shudras and women that you should disregard. We are in the process of releasing a refined edition of the Ramcharitmanas that will be published soon. Scholars hold that over time, teachers of various persuasions have inserted some of their own ideas into all the scriptures. This is somewhat like buying excellent rice and finding two or four pebbles in it that hurt your teeth. A discerning person receives these supremely beautiful scriptures just as one would remove the pebbles from excellent rice and then partake of it. In the Gita, there are no such pebbles. So when you study the scriptures for a few months or a few years, you will find that every day a layer of impurity is removed from your mind. These layers are not two or four — they number in the hundreds. However, gradually, over the course of five or six years, a person's mind generally becomes purified — provided that person genuinely wishes to purify it. If one reads the scriptures merely as a formality, no significant benefit accrues.
A second, more powerful method is for extremely earnest seekers. That is the daily or weekly use of self-examination tools. In my work, 'Moksha Vidyadayini Param Pavan Bhagavat Gita,' I have provided ten such self-examination tools or self-assessment questionnaires. One should look at these and assign oneself scores. Those who are not embarrassed — and one should not be embarrassed about this — should also involve their spouse, children, parents, and others, and ask them which of these negative traits they observe most prominently. By doing this, you will gain a truer understanding, because no ordinary human being wants to see faults in himself; everyone considers himself a very good person. This rule applies to 99% of people. Therefore, if you inquire about these traits collectively, the truth will be revealed to you immediately.
At that point, you will be taught a meditation process through which these negative traits will be quickly eliminated.
However, sharing that meditation process in this group right now would not be beneficial, because that process is taught only when a seeker is very serious and has followed through on the steps described above — filling out the self-examination tools in a group setting and honestly assigning oneself scores.