Vedas are the foremost sacred books of Hinduism. There are four Vedas and they claim to teach a man the highest truths that can lead him to God. The first three Vedas are known as the Triple Vedas
The Rig veda (Veda of Hymns) consists of 1028 hymns (ten books) to gods like Indra and Agni.
The Yajur veda (veda of liturgy) concerns the knowledge of rites. This veda is based on the fig veda. It contains the rules explaining how to perform all rituals. It consists of prose and verse. This veda is indeed a priestly handbook, even describing the rules and regulations of how to make an altar. Sacrifice is one of the most important parts of this veda.
The vast majority of Vedic hymns are addressed to a pantheon of deities who are attracted, generated, and nourished by the offering into the sacred flames and the precisely chanted mantras (mystical formulas of invocation) based on the hymns. Each of these deities may appear to be the supreme god in his or her own hymns, but some gods stand out as most significant. Indra, god of the firmament and lord of the weather, is the supreme deity of the Vedas. India also is a god of war who, accompanied by a host of storm gods, uses thunderbolts as weapons to slay the serpent demon Vritra (the name means storm cloud), thus releasing the rains for the earth. Agni, the god of fire, accepts the sacrificial offerings and transmits them to all the gods. Varuna passes judgment, lays down the law, and protects the cosmic order. Yama, the god of death, sends earthly dwellers signs of old age, sickness, and approaching mortality as exhortations to lead a moral life. Surya is the sun god, Chandra the moon god, Vayu the wind god, and Usha the dawn goddess.
Some of the later hymns of the Rig Veda contain speculations that form the basis for much of Indian religious and philosophical thought. From one perspective, the universe originates through the evolution of an impersonal force manifested as male and female principles. Other hymns describe a personal creator, Prajapati, the Lord of creatures, from whom came the heavens and the earth and all the other gods. One hymn describes the universe as emerging from the sacrifice of a cosmic man (purusha) who was the source of all things but who was in turn offered into the fire by gods. Within the vedic accounts of the origin of things, there is a tension between visions of the highest reality as an impersonal force, or as a creator god, or as a group of gods with different jobs to do in the universe. Much of Hinduism tends to accept all these visions simultaneously, claiming that they are all valid as different facets of a single truth, or ranks them as explanations with different levels of sophistication. It is possible, however, to follow only one of these explanations, such as believing in a single personal god while rejecting all others, and still claim to be following the Vedas. In sum, Hinduism does not exist as a single belief system with one textual explanation of the origin of the universe or the nature of God, and a wide range of philosophies and practices can trace their beginnings somewhere in the hymns of the Vedas.
By the sixth century BC., the Vedic gods were in decline among the people, and few people care much for Indra, Agni, or Varuna in contemporary India. These gods might appear as background characters in myths and stories about more important deities, such as Shiva or Vishnu; in some Hindu temples, also there are small statues of Vedic deities. Sacrificial fire, which once accompanied major political activities, such as the crowning of kings or the conquest of territory, still forms the heart of household rituals for many Hindus, and some Brahman families pass down the skill of memorizing the hymns and make a living as professional reciters of the Vedas. One of the main legacies of Brahmanical sacrifice, seen even among traditions that later denied its usefulness, was a concentration on precise ritual actions and a belief in sacred sound as a powerful tool for manifesting the sacred in daily life.