Krishna explains in the 7th Chapter of B.G. that there are four classes of men who approach Him. There are millions of men in distress, or searching for money, or curious, or searching for knowledge, but only a few come to Krishna, and all of them are mahatma - simply because they have come to the right place, Krishna. That is not by chance, but due to their past pious deeds. No one can approach Krishna without being purified, so this is the process. But no matter what the original motive, if one actually comes to Krishna he is mahatma.
Letter to Hayagriva, 26 September, 1970