Avidya Kama Karma Karyam

Avidya Kama Karma roopa Samasara

The samsara is due to Avidya (ignornce of being complete) which results in Kama (desire to make one self complete) through Karma (finite actions) whcih give rise to Karma Phala (finite results) which will take u to certain Bhoga/lokas like experiences/swarga and to enjoy those finite results u have to have Sharira (a fitting body) for which u have to take birth in that particular environment. This is a big vicious cycle called samsara chakra.

To come out of it there is only one way that is knowing ones true nature which is completely complete paripoorna, in which there is no further scope for improvement. Before knowing one must get qualified to that knowledge by aquiring the sadhana chatustaya sampathi.