Mahavira Jaina and Gautama Buddha were great contemporaries.
Both of them represented the mental upsurge of their age for newness and reform.
Both were the founders of new religions, and both were reformers of the existing society and faith. Both Jaina and Buddha came from the Kshyatriya princely families, and not from the Brahmin priestly class. Both of them denied the authority of the Vedas, and the supremacy of the Brahmins in matters spiritual. Both opposed the prevailing religious practices in forms of rites, rituals, animal sacrifices and superstitions.
Both were apostles of non-violence and of social equality of men. Both emphasized on the code of conduct, morality, ethics and virtue. Both regarded the worldly existence as an evil and the life as full of miseries. Both Jaina and Buddha believed in the cycle of Karma and the chain of birth and rebirth. Both showed the way of escape from the worldly miseries and the pain of karma. Both believed in liberation from bondage by right thought, word and deed. Both carried their message to the people through the language of the people.
With these similarities in the Jaina and the Buddhist thoughts, there were also some differences between the two Jaina believed in extreme penance and self torture to prove the unreality of the body and prescribed hard rules of austerity. But Buddha did not prescribe extreme means and instead advocated the Middle Path.
Similarly, Jainism lay the greatest emphasis on the sanctity of all life and advocated total non-violence towards even the smallest of the creatures, visible or invisible. For this, the Jains practiced extreme caution. They did not cook food or eat after sunset so that insects might not die in fire, and even covered their mouth by cloth to avoid any insect entering into it. Buddhists did not go to that extreme.
On the other hand, the Buddhists rejected the caste system totally and thoroughly, while the Jainas were prepared to tolerate it to some extent. While the Buddhists moved away from the mainstream of Hinduism for a separate existence, the Jainas did not totally give up their association with the Brahmanical influences. In due course, Buddhism spread outside to become a great religion of Asia on its own merit. Jainism, on the other hand, remained confined to the country of its birth. In course of time, Buddhism almost disappeared from India, whereas, Jainism continued to exist as one of the Indian religions.
It was the Hindu liberality and pacifism which ultimately came to regard Buddha as a God, and worshipped him as Divine. Came as it did from the fountain source of Aryan spiritualism, Buddhism got ultimately submerged in the sublime Hindu thought and lost itself in the all pervading Hinduism of the future ages. But, during the course of its rise and spread, it enriched the Indian spiritual and philosophical outlook in varied forms. Both Jainism and Buddhism made great contributions in every sphere of Indian culture, in philosophy, literature, art and architecture with their permanent impression on the Indian life.