abhyasa-yoga-yuktena
cetasa nanya-gamina
paramam purusam divyam
yati parthanucintayan (Gita 8/8)


He who meditates on the Supreme Personality of Godhead, his mind constantly engaged in remembering Me, undeviated from the path, he, O Partha [Arjuna], is sure to reach Me.



In this verse Lord Krsna stresses the importance of remembering Him. One's memory of Krsna is revived by chanting the maha-mantra, Hare Krsna. By this practice of chanting and hearing the sound vibration of the Supreme Lord, one's ear, tongue and mind are engaged. This mystic meditation is very easy to practice, and it helps one attain the Supreme Lord. Purusam means enjoyer. Although living entities belong to the marginal energy of the Supreme Lord, they are in material contamination. They think themselves enjoyers, but they are not the supreme enjoyer. Here it is clearly stated that the supreme enjoyer is the Supreme Personality of Godhead in His different manifestations and plenary expansions as Narayana, Vasudeva, etc.
The devotees can constantly think of the object of worship, the Supreme Lord, in any of His features--Narayana, Krsna, Rama, etc., by chanting Hare Krsna. 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 Krsna 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 Krsna. 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 Krsna, it is certain that at the end of our lives we shall have the same bodily constitution as Krsna.