The Mundaka Upanisad III.I.III beginning yada pashyah pashyate meaning:
When moksa or liberation is achieved one cuts asunder the knots of worldly bondage and attains proximity to the Supreme Lord.
Also one who has achieved moksa is known to be omnicient as is shown in the Chandogya Upanisad VII.XXVI.II beginning na pashyo myritam pashyati na means:
The enlightened one realising the Supreme Lord has realised the atma and all else.
The Supreme Reality is called sat eternal existence in its state of being because of its capacity to divide itself into names and forms.
The Supreme Reality is also called asat or non-existence because of its incapacity to divide itself into names and forms.
This is also given in the Taittiriya Upanisad II.VII beginning asadva idamagre asit meaning: Verily in the beginning this creation was non-existent.
Also in the Brihadaranyaka Upanisad I.IV.VII beginning taddedam tarhayavaya meaning: Verily before the demigod Brahma became the secondary, instrumental cause of creation, the whole creation was dormant in its unmanifested form under the sway of the primary efficient cause.
So because the Supreme Reality of the atma is beyond both sat and asat it is known as being and non-being. The Katha Upanisad I.II.XVIII beginning na jayate mriyate va means:
The soul is unborn, eternal unchangeable and never subject to death.
To be continued ....