Srimad Bhagavatam Canto 07, Chapter 07, Text 46

SB 7.7.46

nirupyatam iha svarthah
 kiyan deha-bhrto ’surah
nisekadisv avasthasu
 klisyamanasya karmabhih
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
My dear friends, O sons of the asuras, the living entity receives different types of bodies according to his previous fruitive activities. Thus he is seen to suffer with reference to his particular body in all conditions of life, beginning with his infusion into the womb. Please tell me, therefore, after full consideration, what is the living entity’s actual interest in fruitive activities, which result in hardship and misery?
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Karmana daiva-netrena jantur dehopapattaye. The living entity receives a particular type of body according to his karma, or fruitive activities. The material pleasure derived in the material world from one’s particular body is based on sexual pleasure: yan maithunadi-grhamedhi-sukham hi tuccham. The entire world is working so hard only for sexual pleasure. To enjoy sexual pleasure and maintain the status quo of material life, one must work very hard, and because of such activities, one prepares himself another material body. Prahlada Maharaja places this matter to his friends, the asuras, for their consideration. Asuras generally cannot understand that the objects of sexual pleasure, the so-called pleasure of materialistic life, depend on extremely hard labor.
Srimad Bhagavatam Canto 07, Chapter 07, Text 45
Srimad Bhagavatam Canto 07, Chapter 07, Text 47