Why did Vyasa write Mahabharata?

Question

I want to know what made Vyasa write the Mahabharata. What was the reason why Mahabhara wrote Mahabharata? Why did he write it in the first place?

Answer 1

Vyasa tells the reader the reason for writing the Mahabharata. It is to teach the reader about the four Purusharthas (goals of life), dharma, artha, kama and moksha and how best to attain these goals. In this process of teaching it gives the reader instruction about how to lead a useful life.

1. The wisdom of this work, like unto an instrument of applying collyrium, hath opened the eyes of the inquisitive world blinded by the darkness of ignorance. As the sun dispelleth the darkness, so both the Bharata by its discourses on religion, profit, pleasure and final release, dispel the ignorance of men. As the full-moon by its mild light expandeth the buds of the water-lily, so this Purana, by exposing the light of the Sruti hath expanded the human intellect. By the lamp of history, which destroyeth the darkness of ignorance, the whole mansion of nature is properly and completely illuminated.

(Mahabharata Adi Parva I)

2. The learned man who recites to other this Veda of Vyasa, reapeth advantage. It may without doubt destroy even the sin of killing the embryo and the like. He that readeth this holy chapter of the moon, readeth the whole of the Bharata, I ween. The man with reverence daily listeneth to this sacred work acquireth long life and ascendeth to heaven.

In former days, having placed the four Vedas on one side and the Bharata on the other, these were weighed in the balance by the celestials assembled for the purpose. And as the later weighed heavier than the four Vedas with their mysteries, from that period it hath been called in the world Mahabharata. Being esteemed superior both in substance and gravity of import it is denominated Mahabharata on account of such substance and gravity of import. He that knoweth its meaning is saved from all sin.

(Mahabharata Adi Parva I)

3. This Bharata consists of a hundred thousand sacred slokas composed by the son of Satyavati, of immeasurable mental power. He that reads it to others, and they that hear it read, attain the world of Brahman and become equal to the very gods. This Bharata is equal unto the Vedas, is holy and excellent; is the worthiest of all to be listened to, and is a Purana worshipped by the Rishis. It contains much useful instruction on Artha and Kama. This sacred history maketh the heart desire for salvation. Learned persons by reciting this Veda of Krishna-Dwaipayana to those that are liberal, truthful, and believing, earn much wealth. Sins such as killing the embryo in the womb, are destroyed assuredly by this.

(Mahabharata Adi Parva LXII)

https://www.sacred-texts.com/hin/m18/m18005.htm

He has composed this, beholding everything with a celestial eye that has been cleansed (strengthened) by varied lore. He has done this, desiring to spread the fame, throughout the world, of the high-souled Pandavas, as also of other Kshatriyas possessed of abundant wealth of energy.