HOW THE GUNAS  FUNCTION?   

rajastamashchaabhibhooya  Sattvam bhavati bhaarata
    rajah Sattvam  tamaishchaiva tamah Sattvam rajastathaa // 14.10 //

O Bharata, Sattva  arises predominating over Rajas and Tamas; likewise Rajas (prevails)  overpowering  Sattva and Tamas; so Tamas  (prevails) over Sattva and Rajas.

The question whether these three Gunas act on the mind  all at a time or each separately at different points of time is answered here.  The Lord says that these Gunas act at different times - each one of them  becoming powerful at any one point of time. At a given time human personality  works under the influence of one predominant Guna when the other two Gunas get  subdued but not totally absent.

Thus when Sattva predominates over Rajas and Tamas it  produces on the mind its own nature of happiness and knowledge ; when Rajas  predominates over the other two it produces passions, desires, attachments and  actions. When Tamas is prominent over Sattva and Rajas it shrouds  discrimination and makes the mind unaware of its nobler duties.

sarvadwaareshu  dehesmin prakaasha upajaayate
    jnaanam  yadaa tadaa vidyaadvivriddham Sattvamityuta // 14.11 //

When through every gate (sense organs) in this body,  the light of intelligence shines, then it may be known that Sattva is  predominant.

In this and next two verses the symptoms are explained  by understanding which their sources i.e. Gunas can be known. The sense organs  through which the body receives the stimuli from the external world are termed  the gates of the body. Through these gates the light of awareness illumines the  objects of the world like power of vision from the eyes, power of hearing for  the ears etc. Each beam of light emanating from each gate illumines one aspect  of the world outside.

When there is 
•unruffled peace of mind, 
•inner harmony, 
•perfect serenity and tranquility, 
•clarity of vision and 
•penetrative insight

then we should understand that Sattva predominates.

When Sattva predominates ears refuse to hear improper  sounds, eyes will not see undesirable sights, tongue avoids anything not proper  and mind is not attracted towards sensual objects. If there is increase of Sattva  there is increase of knowledge.
    lobhah  pravrittir aarambhah karmanaamashamah sprihaa
    rajasyetaani  jayante vivriddhe bharatarshabha // 14.12 //

Greed, activity, the undertaking of actions,  restlessness, longing - these arise when Rajas is predominant, O Best of the  Bharatas.

Sri Krishna enumerates the important qualities of the  mind when Rajas dominates it. 
•Greed - desire to appropriate the property of another. 
•Activity - all activities motivated by selfish desires. 
•Restlessness - lack of enjoyment and quietitude.

These three are interconnected and one succeeds the  other in their impact. Greed leads to selfish activity, activity leads to  unrest over the results of such activities. When one is completely subjugated  by Rajas he feels inexhaustible longing for objects.

Aprakaasho’pravrittishcha  pramaado moha eva cha
    tamasyetaani  jaayante vivriddhe kurunandana // 14.13 //

Darkness, inertness, mis-comprehension and delusion -  these arise when Tamas is predominant, O Descendent of Kuru.

The symptoms when Tamas predominates are given now. 
•Darkness - a condition in which intellect is not capable of arriving at any decision. 
•Inertness - sense of incapacity to undertake any endeavor and lack of enthusiasm to achieve anything in the world. 
•Mis-comprehension - Incapacity to respond to good or bad and miscalculation of one's relationship with others around. Delusion - when such a person fails to understand the outside world he is always deluded.

EFFECTS OF GUNAS

yadaa  sattwe pravriddhe tu pralayam yaati dehabrit
    tadottamavidaam  lokaan amalaan pratipadyate // 14.14 //

If  the embodied one meets death when Sattva is predominant then he attains to the  spotless worlds of the knowers of the Highest.

Sri  Krishna now gives an idea as to the direction in which the mental equipment of  the dead one would reach soon after death. There is always a continuity of  thought in this life. Today's thoughts are an extension of yesterday's thinking  and the thoughts of tomorrow will be conditioned by today's thinking. On the  same analogy the type of thoughts entertained during one's life time will  determine the type of thoughts that will follow after death also. So if the  Sattva Guna is dominant at the time of death one attains the highest realm of  abundant joy.

rajasi pralayam gatwaa karmasangishu  jaayate
    tathaa praleenastamasi moodha yonishu  jaayate // 14.15 //
    Meeting  death in Rajas, he is born among those attached to action; dying in Tamas, he  is born in the womb of the senseless.

If  the mind is under the influence of Rajas at the time it leaves the body, it  takes the embodiment among those who are attached to action. It means that the  mind will seek an appropriate field to exhaust the existing tendencies or  vasanas at the time of death. Similarly, when one dies when Tamas is dominant  one reaches the realm of irrational beings such as animal or vegetable kingdom.

karmanah sukritasyaahuh saattwikam  nirmalam phalam
    rajasastu phalam duhkham ajnaanam tamasah  phalam // 14.16 //

The  fruit of good action, they say, is Sattvic and pure; verily the fruit of Rajas  is pain and ignorance is the fruit of Tamas.

In  this verse The Lord summarizes what He told in the previous verses. The results  obtained by living in the three Gunas are given here.

•Sattva: If one lives a quiet and good life of service, devotion, of love and kindness, of mercy and compassion, it indicates the Sattvic nature of his mind. He achieves inward purity.

 Rajas: Leading a life full of desires and continuous actions to satisfy them always results in sorrows and pain.

 Tamas: Dullness in actions, lack of discriminating capacity and absence of understanding leading to ignorance is the fruit of Tamas.

Sattvaat sanjaayate jnaanam rajaso lobha  eva cha
    pramaadamohau tamaso bhavato’jnaanameva  cha // 14.17 //

From  Sattva arises wisdom, from Rajas greed, mis-conception and delusion and from  Tamas ignorance arise.

When  Sattva is predominant the intellect is enlightened and knowledge awakened.  Rajas creates insatiable cravings, makes one to ignore the feelings of others  and breeds selfish acquisitiveness. Tamas brings forth incapacity to perceive  rightly the world outside and eliminates the power to right judgment.
    oordhwam gacchanti Sattvasthaa madhye  tishthanti raajasaah
    jaghanyaGunavrittisthaa adho gacchanti  taamasaah // 14.18 //

Those  who are abiding in Sattva go upwards, the Rajasic dwell in the middle and the  Tamasic abiding in the function of the lowest Gunas go downwards.

  •Go upwards: Those who are living a pure life of discrimination, clear thinking, right judgment and self-discipline cultivate more and more Sattva qualities in themselves. When the mind is thus quiet it evolves to a higher level.

•Dwell in the middle: Those of Rajasic nature, with all their desires and agitations, ambitions and achievements again and again manifest as human beings till they acquire the required purity.

•Go downwards: Those of Tamasic nature that are full of misconceptions and deluded in their own lust and passions devolve themselves into the lower natures.

This  verse repeats the ideas expressed in the verse which explained the continuity  of existence even after death. It is made clear that all the three Gunas bind  man to attachment; including Sattva which binds us to knowledge and happiness.  Then when will man become free from the contacts of the pluralistic world to  attain Godhood?

So  far we were told the nature of the Gunas the symptoms from which the  predominant Guna could be identified, their reactions on our life and how they  affect our future etc. It was also told that we get the predominant Guna from  our past which influences the present which in turn determines the future. All  these are the causes for the bondage arising out of the Self in us getting identified  with the matter vestures surrounding it.

There  can be release from these bondages only when we transcend all the Gunas. The  three Gunas may be in different proportions present in each one of us but the  true release comes not only when all the Gunas are transcended but also when we  are established in the Spiritual Experience. This process of escaping ourselves  from the subjective shackles on our psychological and intellectual nature is  called Liberation or Moksha.

In  the subsequent verses the path of liberation is described and the Moksha gained  from the right judgment of the world outside is explained.