SB 6.1.46
yatheha deva-pravaras
trai-vidhyam upalabhyate
bhutesu guna-vaicitryat
tathanyatranumiyate
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O best of the demigods, we can see three different varieties of life, which are due to the contamination of the three modes of nature. The living entities are thus known as peaceful, restless and foolish; as happy, unhappy or in-between; or as religious, irreligious and semireligious. We can deduce that in the next life these three kinds of material nature will similarly act.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The actions and reactions of the three modes of material nature are visible in this life. For example, some people are very happy, some are very distressed, and some are in mixed happiness and distress. This is the result of past association with the modes of material nature — goodness, passion and ignorance. Since these varieties are visible in this life, we may assume that the living entities, according to their association with the different modes of material nature, will be happy, distressed or between the two in their next lives also. Therefore the best policy is to disassociate oneself from the three modes of material nature and be always transcendental to their contamination. This is possible only when one fully engages in the devotional service of the Lord. As Krsna confirms in Bhagavad-gita (14.26):
mam ca yo ’vyabhicarena
bhakti-yogena sevate
sa gunan samatityaitan
brahma-bhuyaya kalpate
“One who engages in full devotional service, who does not fall down under any circumstance, at once transcends the modes of material nature and thus comes to the spiritual platform.” Unless one is fully absorbed in the service of the Lord, one is subject to the contamination of the three modes of material nature and must therefore suffer from distress or mixed happiness and distress.