ते तं भुक्त्वा स्वर्गलोकं विशालं क्षीणे पुण्ये मर्त्यलोकं विशन्ति । एवं त्रयीधर्ममनुप्रपन्ना गतागतं कामकामा लभन्ते ॥२१॥
te taḿ bhuktvā svarga-lokaḿ viśālaḿ kṣīṇe puṇye martya-lokaḿ viśanti evaḿ trayī-dharmam anuprapannā gatāgataḿ kāma-kāmā labhante
te — they; tam — that; bhuktvā — having enjoyed; svarga-lokam — heaven; viśālam — vast; kṣīṇe — being exhausted; puṇye — the results of their pious activities; martya-lokam — to the mortal earth; viśanti — fall down; evam — thus; trayī — of the three Vedas; dharmam — doctrines; anuprapannāḥ — following; gata-āgatam — death and birth; kāma-kāmāḥ — desiring sense enjoyments; labhante — attain.
When they have enjoyed the vast pleasures of heaven, the stock of their merits being exhausted, they return to the earthly plane. Thus, those who follow the Vedic rituals, desiring objects of enjoyment, repeatedly come and go in this world.
One who is promoted to the higher planetary systems enjoys a longer duration of life and better facilities for sense enjoyment, yet one is not allowed to stay there forever. One is again sent back to this earth upon finishing the resultant fruits of pious activities. He who has not attained perfection of knowledge, as indicated in the Vedānta-sūtra (janmādy asya yataḥ), or, in other words, he who fails to understand Kṛṣṇa, the cause of all causes, becomes baffled about achieving the ultimate goal of life and is thus subjected to the routine of being promoted to the higher planets and then again coming down, as if situated on a ferris wheel which sometimes goes up and sometimes comes down. The purport is that instead of being elevated to the spiritual world, from which there is no longer any possibility of coming down, one simply revolves in the cycle of birth and death on higher and lower planetary systems. One should better take to the spiritual world to enjoy an eternal life full of bliss and knowledge and never return to this miserable material existence.