Buddha moved among Hindus and spoke their language.
Buddha moved among Hindus and spoke their language.

Hinduism predates Buddhism by two millennia and is the substrate from which Buddhism emerged. Buddha himself was born a Hindu, and the religion he founded was, in many ways, a revolutionary movement within Hinduism. Consequently, despite their differences, the two religions have many concepts in common. Some of them are as ancient as the Vedas, even though Buddhists don't place any importance in these seminal scriptures at the heart of Hinduism.

Dhamma

Buddhists call the natural moral law of the universe dhamma -- a Pali word derived from the Sanskrit word dharma, which has the same meaning. The concept of dharma is so central to Hinduism that some Hindus maintain that the proper name for Hinduism is Sanatana Dharma -- the word "sanatana" means "eternal." Hindus do not consider sanatana dharma a creed, but rather a code of conduct and value system that transcends sectarian leanings or ideological divisions, according to Vedic Knowledge Online. When Buddhists use the term dhamma, however, they are usually referring specifically to the teachings of the Buddha, although they refute the notion that he created them.

Karma

Karma is the law of moral causation that pervades the universe. Simply stated, it means that good actions lead to favorable circumstances and bad actions to unfavorable ones, and that the causative effect can extend across lifetimes. It is a fundamental doctrine in Buddhism that undeniably has its roots in Hinduism. It is conceptually developed in the Upanishads, which are philosophical texts attached to the Vedas that predate Buddhism by at least a millennium. Although Buddhists take a more nuanced approach to karma than Hindus, identifying various types, forms and qualities, the idea was well established by the time the Buddha began teaching.

Samsara

When Buddha spoke of the lifetimes of suffering that every soul must endure until liberated from the cycle of death and rebirth by dedicated intention and practice, he was echoing teachings from the Upanishads. Hindus call the cycle samsara, a word which Buddhists also use. Hindus believe that individual souls choose to live on the wheel of samsara by believing in their separation from the whole, and they get off the wheel by renouncing that separation and immersing themselves in God. Buddhists have a similar belief, but they do not believe in a god with whom the soul can merge.

Nirvana

Both Buddhists and Hindus maintain that getting off the wheel of samsara is the goal of spiritual practice. Hindus call this moksha, or liberation, but Buddhists have a different word. They call it nirvana, which is a word that connotes cessation. Far from being a negative state, or one that one has to die to achieve, it is instead a cessation of the desires, both subtle and gross, that produce the suffering that Buddha taught is their inescapable consequence. Thus, it is similar to the absorption in God-consciousness that Hindus seek, except that, for Buddhists, no god is involved.