The primary purpose of yajnas is to nourish devas. The word deva originally meant gods or light beings. However in due course it was used to denote, senses, organs in the body, breathe, speech, the mind, king, a Brahmana, a venerable being or a demi-god. Yajnas may be performed to worship any of them. Their primary purpose is to invoke the gods and nourish them.
Their secondary purpose is to harness divine power to fulfill desires, overcome difficulties or achieve the four main goals namely Dharma, Artha, Kama and Moksha. Yajnas may also be performed to discharge karmic debt or uphold Dharma as an obligatory duty. The mantras and hymns which are sung during the sacrifices are meant to appease the gods and help the worshippers to fulfill their desires and seek divine protection.
Yajnas bring gods and humans together to achieve their common goals and participate in God’s eternal duties as active participants in the sacrifice of creation. The source of Yajna is God himself. He created the worlds and beings out of a primal sacrifice, which serves as the model for the Yajnas humans perform upon earth. According to Sayana, Vishnu is the lord of the sacrifice. In other words, Yajnas play an important role in the preservation of the worlds and beings.
Yajnas are used for material and spiritual purposes as well as for constructive and destructive purposes. Their essential purpose is the preservation of the worlds. Some yajnas are performed to create, some to preserve and protect and some to destroy and remove obstacles and threats. In the Vedas we find that they are meant to secure progeny, a place in heaven, conjugal bliss, prevent or cure sickness and diseases, ward off death, ensure health and vitality, achieve name, fame and prosperity, cleanse sinful karma, repair relationships, help the ancestors, mark important occasions in the life of an individual such as birth, initiation, marriage, etc., and so on. They are also performed for good rains, fertility, better harvest, protection from calamities, evil spells, natural disasters and the inherited sin of the ancestors.
The Vedas recognize the Yajna as a potent weapon to destroy one’s enemies and rivals in love and marriage. In the Yajurveda and Atharvaveda, several Yajnas are suggested to cast spells and delude people. Any Yajna is incomplete unless it reaches the heaven and fulfills its purpose. In that effort, speech, space, the sacred words of the Vedas, the chanting of the mantras, the devotion and sincerity of the worshippers, the purity of the priests, the sanctity of the ritual place and the perfection shown in its performance play an important role.
Attitude and preparation play an important role in the efficacy of the Yajnas. When yajnas are not performed according to prescribed procedure or when they are performed without reverence or respect, they may either fail to produce the intended results or produce unintended consequences.
The Vedas recognize the Yajna as a potent weapon to destroy one’s enemies and rivals in love and marriage. In the Yajurveda and Atharvaveda, several Yajnas are suggested to cast spells and delude people. Any Yajna is incomplete unless it reaches the heaven and fulfills its purpose. In that effort, speech, space, the sacred words of the Vedas, the chanting of the mantras, the devotion and sincerity of the worshippers, the purity of the priests, the sanctity of the ritual place and the perfection shown in its performance play an important role.
Attitude and preparation play an important role in the efficacy of the Yajnas. When yajnas are not performed according to prescribed procedure or when they are performed without reverence or respect, they may either fail to produce the intended results or produce unintended consequences. In the absence of viable alternatives, the Yajnas offered hope and salvation to people who were in distress or who sought divine intervention to protect themselves from the vagaries of life. Their importance did not diminish with the decline of the Vedic religion because they were assimilated into various other traditions, which subsequently became part of Hinduism.
Depending upon the frequency at which they are performed, Yajna may be classified as periodical sacrifices, occasional sacrifices and situational sacrifices. Periodical sacrifices may be further classified as daily, weekly, fortnightly, monthly, quarterly, seasonal or annual. The daily sacrifices, also known as Paka Yajnas, involve offering of cooked food (paka) to five different kinds of beings. Hence, they were also known as five great sacrifices pancha yajnas. The Sankhayana Sutra divides the Paka Yajnas into four kinds, Huta, Ahuta, Prahuta, And Prâsita. In addition to them, devout Brahmanas has the obligation to perform oblations to the Sun in the morning, afternoon and evening. In the Vedic times, they also made daily offerings of Soma Juice to divinities such as Indra, Soma, Varuna, etc.
The fortnightly sacrifices are the full moon day and half-moon day sacrifices. The right time to perform them are mid-day or when “the sun shines on the top of the trees.” Some Yajnas are seasonal and performed to mark the onset of a specific season such as spring, summer or the fruit bearing season. Some Yajnas have to be performed once in several years.
Occasional sacrifices are those which are performed to mark specific occasions such as festivals, auspicious occasions and important events in the life of an individual. Some of them involve elaborate rituals and prior preparation. Situational sacrifices are performed to address specific problems such as to remove impurities (doshas), misfortune or some calamity. Some Yajnas are considered original or natural (Prakrit), and others their derivatives (vikrit). Only the Prakrit Yajnas are mentioned in detail in the Grihya Sutras. They serve as models for the latter. For example, the Agnistoma sacrifice serves as the model for several Soma sacrifices. The Darsapurnamasa sacrifice is the basis for several sacrifices which are known as Isti. The animals sacrifices, which are associated with the Soma sacrifices serve as the model for all the animal sacrifices.
Depending upon their importance, Yajnas are also classified as main (pradhana) and ancillary (anga). The latter are derived from the former. The ancillary rites may be associated with one or more main sacrifices. Yajnas may also be classified according to the type of offerings. Yajnas where food is the main offering are known as Paka Yajnas. Some Yajnas where oblations are poured are known as Homas. The Yajnas primarily comply with the Vedic methods of worship and value system. However, some are performed according to Tantric beliefs.
Yajnas are also named according to the materials which are used in the sacrifice. For example, the Yajna where knowledge is transmitted is known as Jnana Yajna. The sacrifice of gifts is known as Dana Yajna. The sacrifice which is performed to propitiate the earth before cultivating the land is known as Bhu-Yajna. The Vedas contain references to many Yajnas where animals are sacrificed as offerings. The offerings are mainly cooked food, food grains, fruit, seeds, butter, ghee, oil, water, milk, curd, honey, wood of different kinds, perfumes or scented materials, incense, leaves, kusa grass, grass leaves, prayers, chants, etc.
The simplest form of yajna is the domestic ritual performed by the householder who would offer simple oblation into the sacred fire lit in his house. A more complicated version involves setting up of three to five fires and pouring of offerings into them such as food grains, ghee or butter, and other vegetable substances by chosen and qualified priests, chanting mantras simultaneously, invoking various gods especially Agni, Indra, Varuna etc. Householders also
Some yajnas are performed on large scale for the general welfare of the entire community, to increase fertility of soil, to invite rains, to welcome peace and wealth etc. Depending upon the degree of complexity, these yajnas may last from a few hours to several days. The number of priests participating and conducting the ceremony would depend upon the nature and objective for which it is performed.
Yajnas may be performed ritually with material offerings or spiritually with mental offerings. The latter are known as Antar Yajnas. They are essentially meditative practices or approaches to internal worship or mental worship. You may consider them as the basis for the development of classical Yoga. In them, the model of the Yajna is internalized, whereby the body becomes the sacrificial altar, the mind becomes the priest and the deity Yajna, the senses, breath, organs of actions and speech represent the divinities, thoughts and prayers become offerings, while the Self acts as the recipient of the offering.