The Lord says, “I am the knower of the field of activities in every individual body.” The individual may be the knower of his own body, but he is not in knowledge of other bodies. The Supreme Personality of Godhead, who is present as the Supersoul in all bodies, knows everything about all bodies. He knows all the different bodies of all the various species of life. A citizen may know everything about his patch of land, but the king knows not only his palace but all the properties possessed by the individual citizens. Similarly, one may be the proprietor of the body individually, but the Supreme Lord is the proprietor of all bodies. The king is the original proprietor of the kingdom, and the citizen is the secondary proprietor. Similarly, the Supreme Lord is the supreme proprietor of all bodies.
The devotee can constantly think of the object of worship, the Supreme Lord, in any of His features — Narayana, Krishna, Rama, etc. — by chanting Hare Krishna. This practice will purify him, and at the end of his life, due to his constant chanting, he will be transferred to the kingdom of God. Yoga practice is meditation on the Supersoul within; similarly, by chanting Hare Krishna one fixes his mind always on the Supreme Lord. The mind is fickle, and therefore it is necessary to engage the mind by force to think of Krishna. One example often given is that of the caterpillar that thinks of becoming a butterfly and so is transformed into a butterfly in the same life. Similarly, if we constantly think of Krishna, it is certain that at the end of our lives we shall have the same bodily constitution as Krishna