वन्दे तं सात्विकम् शिवम्

ఆంగికం భువనం యస్య - వాచికం సర్వ వాఞ్మయం |
ఆహార్యం చంద్రతారాది - తం వందే సాత్వికం శివం ||

आन्गिकम् भुवनम् यस्य - वाचिकम् सर्ववाङमयम् ।
आहार्यम् चन्द्र तारादि - तं वन्दे सात्विकम् शिवम् ॥


A beautiful simple pithy SlOkam summarizing whole of naaTya Saastram. There are 4 types of 'abhinayam' (enactment) in naaTya Saastram. They are aangikam, vaachikam, aahaaryam, saatvikam.
Aangikam comprises all the physical postures.
Vaachikam includes all the sung and spoken expression including enactment of emotions.
Ahaaryam is all about decoration and ornamentation.

Satvikam is the final and the essence of all abhinayam. It is like the life of dance.

This SlOkam describes how all these 4 aspects of abhinaya are parts of Siva.

Siva's description as ashTamUrti (8 aspects of manifestation) comprises of the whole universe completely. Thus, the whole universe is His physical expression - aangikam.

What comes after the physical expression is spoken, sung and emotive display. Siva is eulogized as "trayeemUrti" in His ashTOttara Sata naamaavaLi (108 divine names.) This name means, He is the very embodiment of vEda-s. Elsewhere, He is described as "vEda geetaH" - one whose praise is the vEda-s. Adi Sankara composed "vEda saara Siva stOtra" thereby concluding that the essence of vEda describes Siva. There is the following paadam of a SlOkam: "వేదః శివః శివో వేదః" (वेदश्शिवः शिवोवेदः) which means, Veda is Siva Himself and Siva is Veda itself. And Veda comprises ALL knowledge!
So, His spoken, sung and emotive expression is vEda, the mother of all knowledge - vaachikam.

Who is not mesmerized by the beauty of starlit sky whose emperor is Chandra! The fathomless sky with all those celestial elements is full of wonders and extends beyond all imaginable limits. All that forms His incomparable ornamentation or embellishment - aahaaryam.

Finally, the saatvika aspect! By "living" the expression, the performer invokes the feeling of the expression among the onlookers. The purer, simpler, calmer, diviner the mind of the performer, the greater the effect it produces. This is the soul of the performance, the essential aspect.
The very presence of some seasoned and dedicated performers is enough for captivating the audience. It is because those artistes are so completely involved in their role. Being in the 'present moment' completely, they captivate the audience and take them along into the role and the story. This is nothing but saatvikata! (In rajas or tamas one is not completely in the present moment.)

Siva who is the sat-chit-aananda swarupa is the very essence and embodiment of all saatvikata! (State of being the Truth (sat) is saatvikata.)

While the former three aspects of abhinaya cannot jointly or severally produce the 'effect', saatvikam can, on its own! (For example, without any props, a thespian can enact a great scene whereas props by themselves cannot achieve that!!)
The relation between the former three aspects and the final one is like the relation between manifestation and the unmanifest truth. That is, jagat and brahma!
The manifest universe is transient/mithya where as the unmanifest is the truth. Siva is sattvam, the truth.

సన్మార్గాలోకనాయ వ్యపనయతు స నః తామసీం వృత్తిం ఈశః |
सन्मार्गालोकनाय व्यपनयतु स नः तामसीम् वृत्तिम् ईशः ।
sanmaargaalOkanaaya vyapanayatu sa naH taamasIm vRttim eeSaH.
- Malavikaagnimitram by Kavikulaguru Kalidasa.

May that Lord Siva make us to behold the Truth (sat) by diverting us from stupor (tamas.)