Duty of a Kshastriya
The duty of a Kshastriya is outlined in the Kurma Purana:
The kshatriyas constitute the second of the four classes. They were created from Brahma’s arms. The duties of kshatriyas include dana (donation of alms), adhyayana (studying) and performing yajnas (sacrifices). But their primary duties are to take up arms and fight, It is their job to punish the evil and protect the good. A kshatriya who performs these tasks well, attains Indra’s residence of Indraloka.
This is further asserted in Section 55 (LV) of the Rajadharmanushashana Parva under the Shanti Parva:
"Bhishma said, 'As the duty of the Brahmanas consists of the practice of charity, study, and penances, so the duty of Kshatriyas is to cast away their bodies, O Krishna, in battle. A Kshatriya should stay sires and grandsires and brothers and preceptors and relatives and kinsmen that may engage with him in unjust battle. This is their declared duty. That Kshatriya, O Kesava, is said to be acquainted with his duty who slays in battle his very preceptors if they happen to be sinful and covetous and disregardful of restraints and vows. That Kshatriya is said to be acquainted with his duty who slays in battle the person that from covetousness disregards the eternal barriers of virtue. That Kshatriya is said to be acquainted with duty who in battle makes the earth a lake of blood, having the hair of slain warriors for the grass and straw floating on it, and having elephants for its rocks, and standards for the trees on its banks. A Kshatriya, when challenged, should always fight in battle, since Manu has said that a righteous battle (in the case of a Kshatriya) leads to both heaven and fame on earth.'
The Manu Smriti also has something to say about this. This is from the first chapter.
- The Kshatriya he commanded to protect the people, to bestow gifts, to offer sacrifices, to study (the Veda), and to abstain from attaching himself to sensual pleasures;
Chapter 7 describes in detail:
I will declare the duties of kings, (and) show how a king should conduct himself, how he was created, and how (he can obtain) highest success.
A Kshatriya, who has received according to the rule the sacrament prescribed by the Veda, must duly protect this whole (world).
A king who, while he protects his people, is defied by (foes), be they equal in strength, or stronger, or weaker, must not shrink from battle, remembering the duty of Kshatriyas.
Not to turn back in battle, to protect the people, to honour the Brahmanas, is the best means for a king to secure happiness.
Those kings who, seeking to slay each other in battle, fight with the utmost exertion and do not turn back, go to heaven.
But the (Kshatriya) who is slain in battle, while he turns back in fear, takes upon himself all the sin of his master, whatever (it may be);
And whatever merit (a man) who is slain in flight may have gained for the next (world), all that his master takes.
From the same chapter:
Chariots and horses, elephants, parasols, money, grain, cattle, women, all sorts of (marketable) goods and valueless metals belong to him who takes them (singly) conquering (the possessor).
A text of the Veda (declares) that (the soldiers) shall present a choice portion (of the booty) to the king; what has not been taken singly, must be distributed by the king among all the soldiers.
Thus has been declared the blameless, primeval law for warriors; from this law a Kshatriya must not depart, when he strikes his foes in battle.
144, The highest duty of a Kshatriya is to protect his subjects, for the king who enjoys the rewards, just mentioned, is bound to (discharge that) duty.
The main duties of a Kshastriya seems to be warfare, taking care of subjects, and giving gifts.
Duty of a Vaishya
In the Bhagavad Gita, Krishna explains to Arjuna the duties of the four Varnas. The description of the duties the Vaishyas perform can only closely be found here:
कृषिगौरक्ष्यवाणिज्यं वैश्यकर्म स्वभावजम्।
परिचर्यात्मकं कर्म शूद्रस्यापि स्वभावजम्।।18.44।।
Farming, cattle raising and business are the qualities of work for the vaisyas, and for the sudras there is labor and service to others.
The Rigveda slightly references the duties of a Vaishya here:
BrAhmano asya mukham Asit
BAhu rAjanyah krtah
Uru tad asya yad vaishyah
PAdbhyAm shudro ajAyata ||
His key part (or mouth) was the man of the word (BrAhmana). Into the Prince (rAjanya), (referring to Kshatriyas) his arms were made. While his wideness (Uru;Thighs) became the producers (Vaishya). His power of movement (feet) gave birth to the man of service (Shudra).
Rig Veda 10.90.12 Or VAjasaneyi SamhitA 31.11.
Duty of a Shudra
Shudras are treated the worst of all Varnas. It is truly unfortunate, but unchangeable.
Chapter 1 of the Manusmriti states their duties briefly:
One occupation only the lord prescribed to the Sudra, to serve meekly even these (other) three castes.
Here is what the great Sri Medhatithi says about the interpretation of this verse:
The Lord’, Prajāpati, ordained ‘one function, for the Śūdra’; [in the form]—‘Thou shalt perform the ‘service of the said castes,’—i.e., of the Brāhmaṇa, Kṣatriya and Vaiśya;—‘Ungrudging’—i.e., without complaining; no resentment should be felt even in the mind. ‘Service’ stands for attending; i.e., doing of acts conducive to their convenience; such as massage of the body, and the obeying of wishes. What is mentioned here is only such function of the Śūdra as leads to visible results (in the shape of livelihood); and in as much as the phrase ‘one only’ is not injunctive, it does not preclude the giving of gifts (and such other acts, leading to invisible results); specially as we shall find later on the actual injunction of these acts (for the Śūdra also). And it will be on that occasion that we shall set forth the classification of sacrifices and other acts (as to which of these should be done by which castes, and so forth). (91).
In Section LXXII of the Rajadharmanushashana Parva of the Shanti Parva of the Mahabharata, Vayudeva describes the duties of the Shudras to Pururavas:
The Brahmana, O best of kings, has sprung from the mouth of Brahman. The Kshatriya has sprung from his two arms, and the Vaisya from his two thighs. For waiting upon these three orders, O ruler of men, a fourth order, viz., the Sudra, sprung into life, being created from the feet (of Brahman). Originally created thus, the Brahmana takes birth on earth as the lord of all creatures, his duty being the keep of the Vedas and the other scriptures. Then, for ruling the earth and wielding the rod of chastisement and protecting all creatures, the second order, viz., the Kshatriya was created. The Vaisya was created for supporting the two other orders and himself by cultivation and trade, and finally, it was ordained by Brahman that the Sudra should serve the three orders as a menial.
One interesting thing to note is that Shudras are not a caste that is born into. Rather, to be a Shudra is to follow wicked, unrighteous, or deceitful actions.
The Srimad Bhagavatam clearly states and defines a Shudra:
These teachings are not to be imparted to persons who are wicked, haughty, barbarous, foul in conduct, hypocritical, given to sensuous indulgences, interested exclusively in their worldly concerns, who are without devotion to Me or who persecute My devotees.
This is further asserted in the Brahma Purana, when Shiva Himself says this:
Na yonirnaapi samskaaro na Shrutirnacha santatih, Kaaranaani Dwijasttvasya vrutthamevatu vidheeyatey
It is not by birth, samskara, knowledge of Vedas and by the Offspring that a person possesses, but Brahmanatva (i.e how much a person is close to the rank of a Brahmin) a decisive factor merely on one’s own behavior, conduct and actions!
What's even more interesting is that the Srimad Bhagavatam says Vishnu says that Shudras cannot learn about his teachings.
However, in the Yajur Veda, Vishnu says that Shudras and even wicked men may read his teachings or the Vedas:
I do hereby address this salutary speech for the benefit of humanity, for the Brahmanas, the Kshatriyas, the Sudras, the Vaishas, the kinfolk and the men of the lowest position in society. (Yajur Veda 26.2)
The Yajur Veda contradicts the Srimad Bhagavatam, but the Yajur Veda must be true since it is one of the 4 Vedas. Thus, even Shudras may read the Vedas.
Duty of a Brahmin
Upon request, I was asked to include the duties of a Brahmin as well.
The duties of a Brahmin are loosely relayed in the Parashara Smriti:
- A Brahman, who is given to observe the six duties of his caste, who worships the deities and hospitably receives the guests ; whose meals consist of what remains after(daily) offerings made (on the fire), has never to suffer from misery or want.
sandhyA snAnam japo homo devatAtithipujanam |
Atithyam vaiswadevam cha shatkarmAni dine dine || PS 1.39
- Ablution and prayer, inaudible recitation (of sacred words), burnt- offerings, the worship of gods, hospitality to guests unexpectedly come, and offerings made in the name of the Visvadevam, — these are the six duties to be performed every day.
The six duties of a Brahmin are more clearly outlined in the Manu Smriti:
10.75. Teaching, studying, sacrificing for himself, sacrificing for others, making gifts and receiving them are the six acts (prescribed) for a Brahmana.
10.76. But among the six acts (ordained) for him three are his means of subsistence, (viz.) sacrificing for others, teaching, and accepting gifts from pure men.
Vashishtha says any Brahmin who does not follow these six acts are demoted to the Varna of a Shudra:
Brahmins who are not learned, who do not teach, or who do not maintain the sacred fires become equal to S´udras. 2 On this point they cite a verse of Manu: When, without studying the Veda, a twice-born man strives after other matters, he quickly sinks to the level of a S´udra in this very life together with his descendants. (Vashishtha Dharma Sutra 3.4)
From the same Sutra, Vashishtha outlines the normal routines a Brahmin should do in their life:
He should be intent on privately reciting the Veda, offering sacrifices, and begetting offspring. He should honour anyone who comes to his house by rising up to meet him, offering him a seat, and giving kind greetings and unstinting praise; and all creatures by giving them food according to his ability.
When a Brahmin always carries water with him, always wears the sacrificial cord , always recites the Veda privately, avoids the food of outcastes, has sexual intercourse with his wife during her season, and offers sacrifices according to the rules, he does not fall from the world of Brahman. (Vashishtha Dharma Sutra 8.17)
The Bhagavad Gita gives a short description of the conduct a Brahmin should behave as.
Serenity, control of the sense, austerity, purity, straight-forwardness, knowledge, insight, and faith in the Supreme Being - these are a Brahman's duties born of his own nature. (BG 18.42)
Furthermore, in the Varna Ashrama of the Brahma Purana, it states this:
The translation of this means roughly:
In times of emergency, a brahmana is allowed to adopt the livelihoods of kshatriyas or vaishyas to earn a living.
I hope this answered your questions! :)