When a living entity comes in contact with the material creation

Bhagavad Gita As It Is Chapter 3:36-37
By His Divine Grace A.C.Bhaktivedanta Swami

Although the living entity sometimes does not want to act in sin, he is still forced to act. Sinful actions are not, however, impelled by the Supersoul within, but are due to another cause…
When a living entity comes in contact with the material creation, his eternal love for Krishna is transformed into lust…
Therefore, lust is the greatest enemy of the living entity, and it is lust only which induces the pure living entity to remain entangled in the material world…This material creation is created by the Lord to give facility to the conditioned souls to fulfill these lustful propensities, and when completely baffled by prolonged lustful activities, the living entities begin to inquire about their real position.