Ksana-tat-kramayoh samyamat vivekajam jnanam.
= moment; tat-kramah = its order, succession; samyamat
= by performing samyama; vivekajam = born of awareness of reality; jnanam
Knowledge born of awareness of Reality by performing samyama on moment and (the process of) its succession.(III-53)
We live in a world of illusion, maya. What we perceive through the senses is not reality. We perceived matter as a continuous solid phenomenon but scientific discoveries have revealed how there is huge space between various sub-atomic particles. Sunlight seems to be coming to us continuously but in reality it is a quick succession of small "packets" (quanta).
Just like the water flowing in the river is not same at a given moment, our body looking so solid is changing every second due to change of its smallest unit, cells. Everything is changing every second but we do not perceive that. The time creates this illusion.
The static pictures on a cinema reel create an impression of a movie when projected on a screen in quick succession with a particular interval of time (less than one tenth of a second). This small unit of time is called KSANA. And the quick order with which KSANA succeeds one after another is KRAMA. By performing Samyama on KRAMA, a yogi "sees" beyond the changing phenomenon and gets the knowledge of Reality which is permanent, the basis of all creation.