The concept of karma is often discussed as an inscrutable element that operates in a mysterious way. Srila Prabhupada corroborates this in his purport to Srimad Bhagavatam 3.31.44. Here he writes: "It is clear that a particular body is given to the living entity for a particular type of activity. This process is going on perpetually, from a time which is impossible to trace out. Vaisnava poets say, therefore, anadi arama-phale, which means that these actions and reactions of one's activity cannot be traced, for they may even continue from the last millennium of Brahma's birth to the next millennium. We have seen the example in the life of Narada Muni. In one millennium he was the son of a maidservant, and in the next millennium he became a great sage."