Srimad Bhagavatam Canto 06, Chapter 12, Text 15

SB 6.12.15

sattvam rajas tama iti
 prakrter natmano gunah
tatra saksinam atmanam
 yo veda sa na badhyate
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
One who knows that the three qualities — goodness, passion and ignorance — are not qualities of the soul but qualities of material nature, and who knows that the pure soul is simply an observer of the actions and reactions of these qualities, should be understood to be a liberated person. He is not bound by these qualities.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
As the Lord explains in Bhagavad-gita (18.54):
 
brahma-bhutah prasannatma
 na socati na kanksati
samah sarvesu bhutesu
 mad-bhaktim labhate param
 
“One who is transcendentally situated at once realizes the Supreme Brahman and becomes fully joyful. He never laments or desires to have anything; he is equally disposed to every living entity. In that state he attains pure devotional service unto Me.” When one attains self-realization, the brahma-bhuta stage, one knows that whatever happens during his life is due to the contamination of the modes of material nature. The living being, the pure soul, has nothing to do with these modes. In the midst of the hurricane of the material world, everything changes very quickly, but if one remains silent and simply observes the actions and reactions of the hurricane, he is understood to be liberated. The real qualification of the liberated soul is that he remains Krsna conscious, undisturbed by the actions and reactions of the material energy. Such a liberated person is always jubilant. He never laments or aspires for anything. Since everything is supplied by the Supreme Lord, the living entity, being fully dependent on Him, should not protest or accept anything in terms of his personal sense gratification; rather, he should receive everything as the mercy of the Lord and remain steady in all circumstances.
Srimad Bhagavatam Canto 06, Chapter 12, Text 14
Srimad Bhagavatam Canto 06, Chapter 12, Text 16