SB 9.19.20
drstam srutam asad buddhva
nanudhyayen na sandiset
samsrtim catma-nasam ca
tatra vidvan sa atma-drk
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
One who knows that material happiness, whether good or bad, in this life or in the next, on this planet or on the heavenly planets, is temporary and useless, and that an intelligent person should not try to enjoy or even think of such things, is the knower of the self. Such a self-realized person knows quite well that material happiness is the very cause of continued material existence and forgetfulness of one’s own constitutional position.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The living entity is a spiritual soul, and the material body is his encagement. This is the beginning of spiritual understanding.
dehino ’smin yatha dehe
kaumaram yauvanam jara
tatha dehantara-praptir
dhiras tatra na muhyati
“As the embodied soul continually passes, in this body, from boyhood to youth to old age, the soul similarly passes into another body at death. The self-realized soul is not bewildered by such a change.” (Bg. 2.13) The real mission of human life is to get free from encagement in the material body. Therefore Krsna descends to teach the conditioned soul about spiritual realization and how to become free from material bondage. Yada yada hi dharmasya glanir bhavati bharata. The words dharmasya glanih mean “pollution of one’s existence.” Our existence is now polluted, and it must be purified (sattvam suddhyet). The human life is meant for this purification, not for thinking of happiness in terms of the external body, which is the cause of material bondage. Therefore, in this verse, Maharaja Yayati advises that whatever material happiness we see and whatever is promised for enjoyment is all merely flickering and temporary. Abrahma-bhuvanal lokah punar avartino ’rjuna. Even if one is promoted to Brahmaloka, if one is not freed from material bondage one must return to this planet earth and continue in the miserable condition of material existence (bhutva bhutva praliyate). One should always keep this understanding in mind so as not to be allured by any kind of sense enjoyment, in this life or in the next. One who is fully aware of this truth is self-realized (sa atma-drk), but aside from him, everyone suffers in the cycle of birth and death (mrtyu-samsara-vartmani). This understanding is one of true intelligence, and anything contrary to this is but a cause of unhappiness. Krsna-bhakta — niskama, ataeva ‘santa.’ Only a Krsna conscious person, who knows the aim and object of life, is peaceful. All others, whether karmis, jñanis or yogis, are restless and cannot enjoy real peace.