sukham duhkham mrtir janma
sapo ’nugraha eva ca
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Because of the actions of the Supreme Lord’s external energy, the living entities are conditioned in contact with material bodies. The dualities of happiness and distress, birth and death, curses and favors, are natural by-products of this contact in the material world.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In Bhagavad-gita we find, mayadhyaksena prakrtih suyate sa-caracaram: the material world works under the direction of the goddess Durga, the material energy of the Lord, but she acts under the direction of the Supreme Personality of Godhead. This is also confirmed in the Brahma-samhita (5.44):
chayeva yasya bhuvanani bibharti durga
Durga — the goddess Parvati, the wife of Lord Siva — is extremely powerful. She can create, maintain and annihilate any number of universes by her sweet will, but she acts under the direction of the Supreme Personality of Godhead, Krsna, not independently. Krsna is impartial, but because this is the material world of duality, such relative terms as happiness and distress, curses and favors, are created by the will of the Supreme. Those who are not narayana-para, pure devotees, must be disturbed by this duality of the material world, whereas devotees who are simply attached to the service of the Lord are not at all disturbed by it. For example, Haridasa Thakura was beaten with cane in twenty-two bazaars, but he was never disturbed; instead, he smilingly tolerated the beating. Despite the disturbing dualities of the material world, devotees are not disturbed at all. Because they fix their minds on the lotus feet of the Lord and concentrate on the holy name of the Lord, they do not feel the so-called pains and pleasures caused by the dualities of this material world.