In the Bhagavad-Gita, Krishna says (chapter 4, verse 13):
According to the three modes of material nature and the work ascribed to them, the four divisions of human society were created by Me. And, although I am the creator of this system, you should know that I am yet the non-doer, being unchangeable.
When a person (or society) suffers enough on the way to reach sense pleasure, one (or society) tries to accept certain regulating principles of behavior. This attempt already contains the component of virtue. From now on, a person is able to accept the system offered by the Lord which is intended for step-by-step sequential transformation from material to spiritual consciousness.
The above mentioned capabilities of people in society provide execution of four social functions. Mentally-developed persons are usually thought leaders of society. Ones with physical strength and strength of mind are its protectors. Producers ensure economic growth and laborers and servants help other social classes realize their ideas. Figuratively speaking, these four functions constitute different parts of one body and have their own terms in Sanskrit:
1) Intellectuals – religious figures (brahmanas) – the head.
2) Leaders-warriors (kshatriyas) – the arms.
3) Farmers-producers (vaishyas) – the belly.
4) Laborers-servants (shudras) – the legs.
No one can arrange functioning of society when neglecting these four classes. For harmonious functioning of society, there are required:
1) Intellectuals who advise and indicate ways of society development;
2) Producers (farmers) and merchants who create material values and provide food;
3) Laborers who do hard work;
4) Rulers who ensure the harmonious collaboration among these three classes and warriors who protect everyone from enemies from within and without.
As it is impossible to say which part of the body is more important, so it is impossible to say which social class is more important. Once the matter of priority rises, any system turns into the system of privileges and humiliation. Considering the psychology of persons influenced by the three gunas of material nature, it can be said that success of society depends on which guna persons carrying out these functions are influenced by. If, for instance, a person under the influence of ignorance executes duties of a counselor, society develops according to principles of violence and cruelty within the state and conducts an invasive foreign policy. If a counselor is influenced by the guna of passion, then such a person is sure to divide society into friends and enemies (clans). And if one is influenced by the guna of goodness, such a person will lead society to the overall equality and become the source of overall happiness (without creating unnecessary conflicts). People influenced by ignorance abridge people’s freedom because they think that only they have rights for enjoyment and domination over this world (dictatorial rulers). Those in the guna of passion lead society to freedom of senses (I can do what I want) for the sake of sense pleasure (democratic states). In goodness, moderation of senses is proposed for the sake of freedom from suffering and anxiety (the Aryan society). There is one more category of people, the Lord’s devotees, who suggest the freedom of senses but for the sake of the Lord’s satisfaction (inhabitants of the spiritual world).