Krsna is the Supreme Personality of Godhead. How is that? Because He conforms in exact detail to descriptions of the Supreme Being, the Godhead. In other words, Krsna is the Godhead because He is all-attractive. Outside the principle of all-attraction, there is no meaning to the word “Godhead.” How is it one can be all-attractive? First of all, if one is very wealthy, if he has great riches, he becomes attractive to the people in general. Similarly, if someone is very powerful, he also becomes attractive, and if someone is very famous, he also becomes attractive, and if someone is very beautiful or wise or unattached to all kinds of possessions, he also becomes attractive. So from practical experience we can observe that one is attractive due to (1) wealth, (2) power, (3) fame, (4) beauty, (5) wisdom and (6) renunciation. One who is in possession of all six of these opulences at the same time, who possesses them to an unlimited degree, is understood to be the Supreme Personality of Godhead. These opulences of the Godhead are delineated by Parasara Muni, a great Vedic authority.

We have seen many rich persons, many powerful persons, many famous persons, many beautiful persons, many learned and scholarly persons, and persons in the renounced order of life unattached to material possessions. But we have never seen any one person who is unlimitedly and simultaneously wealthy, powerful, famous, beautiful, wise and unattached, like Krsna, in the history of humanity. Krsna, the Supreme Personality of Godhead, is a historical person who appeared on this earth 5,000 years ago. He stayed on this earth for 125 years and played exactly like a human being, but His activities were unparalleled. From the very moment of His appearance to the moment of His disappearance, every one of His activities is unparalleled in the history of the world, and therefore anyone who knows what we mean by Godhead will accept Krsna as the Supreme Personality of Godhead. No one is equal to the Godhead, and no one is greater than Him. That is the import of the familiar saying “God is great.”

From Srila Prabhupada’s preface to “Krsna” book.