Bhagwad Gita - Post 230

Verse 26

He who is free from attachment, non-egoistic, endowed with firmness and enthusiasm and unaffected by success or failure, is called Sattwic.

Sattvic action is defined once again. It is an action performed by those people who are free from attachment, who do not have any kind of a trace of egoism on their part, and are full of enthusiasm for the work. It is not fatigue but enthusiasm, zest, and an indefatigability that is felt before undertaking any work. 

Utsāha, which is enthusiasm, spiritedness, and a love for what is good, should be the motive behind performing action, whether one succeeds or not. This is because, as mentioned earlier, the fruit of an action is not in anyone’s hand. The fruit is the product of the cooperative activity of five factors. 

Therefore, if we do something to the best of our ability but have not succeeded, it is because we have not taken into consideration the other four aspects. Finally, one cannot succeed in life unless one is practically omniscient in nature. 

An ordinary person cannot know what consequence will follow from what action, because we cannot know all aspects of the matter at the same time. Sattvic karma is free from the longing to achieve its fruit, free from egoism, filled with enthusiasm, work undertaken spontaneously by oneself for the welfare of all people.

Verse 27

Passionate, desiring to obtain the rewards of actions, cruel, greedy, impure, moved by joy and sorrow, such an agent is said to be Rajasic.

Here is the description of a person who is full of desires, passions and attachments, desiring for rewards for his actions. 

He is swayed by passion (raaga) and eagerly seeks the fruit of his work. He is ever greedy (Lubdhah), never satisfied with what he gains. His thirst is insatiable because his desires multiply from moment to moment.

When a man, full of desires and passions, he never hesitates to injure another, if such injury were to win his end. He is blind to the amount of sorrow he might bring to others; he is concerned only with the realisation of his ulterior motives. When such a man becomes maliciously resolved to gain his own ends, he becomes impure (Ashuchih), meaning "immoral."

It is but natural that such a person  acts in his blinding desires, comes to live, all through his embodied existence, a sad life of agitations, moved by joys and sorrows, "full of delight and grief," (Harsha-Shoka-Anvitah). This completes the picture of a man who is a 'passionate' (Rajasic) "doer."

Verse 28

Unsteady, dejected, unbending, cheating, malicious, vulgar, lazy and procrastinating—such an agent is called Tamasic.

Sree Krishna now gives a description of tāmasic workers. Their mind is blotted with negative obsessions and thus they are ayuktaḥ (undisciplined). The scriptures give injunctions regarding what is proper and improper behavior.

But workers in the mode of ignorance are  obstinate in their views, for they have closed their ears and mind to reason. Thus, they are often śhaṭhaḥ (cunning) and naiṣhkṛitikaḥ (dishonest or vile) in their ways. 

They are prakṛitaḥ (vulgar) because they do not believe in controlling their animal instinct. Though they may have duties to perform, they see effort as laborious and painful, and so they are alasaḥ (slothful) and dirgha-sutri (procrastinating). 

Their ignoble and base thoughts impact them more than anyone else, making them viṣhadi (unhappy and morose).

The Srimad Bhagavatam also describes types of performers of actions:

sattvikaḥ karako sangi ragandho rajasaḥ smṛitaḥ

tamasaḥ smriti-vibhrashto nirguṇo mad-apashrayah 

“The worker who is detached is sattvic in nature; the one who is excessively attached to action and its results is rajasic; one who is devoid of discrimination is tamasic. But the worker who is surrendered to me is transcendental to the three modes.”

Love.