The one which ought to be understood and after which a person attains the divine bliss is the real knowledge.
However, that pervades and fills the entire universe; can sense everything but has no senses, protects everything without any expectation, has no characteristics of own but enjoys all characters. It resides in and out of everything, living or otherwise. It is the soul of moving or stationary objects. It lies near and far as well. It is invisible but omnipresent.
Soul experiences all products made of the qualities (Gunas as Sattvic,Rrajas, and Tamas) that emerge in nature. And this contact of Atma or Purusha with Prakruti’s qualities determine the appearance of Jeevatma in good or bad forms in the succeeding births.
A person who understands the above doctrine of Purusha and Prakrit has no rebirth though he/she discharges the enjoined duties.
Some people gain the divine bliss of no rebirth through pure and fine meditation and penance (Bhakti yoga): some with the knowledge gained from holy scriptures(Gnana yoga) and some others by selfless actions(karma yoga). The unintelligent persons simply practice what the scholars preach but unaware of the real thing or truth. However, even they also successfully overcome the trouble of life and death. Therefore, the various forms and types, living or non-living, seen in the universe, are actually the result of the permutation and combinations of Prakruti(Kshetra) and Purusha(Kshetragnan) only.
One who sees the God as unbiased and indestructible all that get destroyed, is said to have the real vision. Such person will also realize the fact that atma or soul is not the real doer(kartha) but it’s the result of prakruti only. To be precise, human being is an example of and witness to the existence of God. The true devotee attains the abode of god by understanding all the above through dedication and selflessness.
Source: Chapter "Kshetra Kshetragna vibaga yoga ", BhagvadGita