What is yagna that has been described as niyat karma by Gita?

Describing on the nature of yagna Lord krishna says
       brahmarpanam brahma havir, brahmagnau brahmana hutam
         brahmaiva tena gantavyam, brahma-karma-samadhina 
                                              -B.G. CHAP-4 SLOKA 24
English Translation-“Since both the dedication and the oblation itself are God, and it is the Godlike teacher who offers the oblation to the fire which is also God, the attainment, too, of the man whose mind is set on Godlike action is God himself.”


The emancipated man’s yagya is God, what he offers as oblation is God, and the sacred fire to which the sacrifice is made is also God. That is to say that what is offered by the Godlike worshipper to the sacred fire that is an embodiment of God is also God himself.That which is worthy of being secured by the man whose actions have been dissolved and stilled by God’s loving touch is also God. So this man does nothing; he only acts for the good of others.

These are attributes of the realized sage who has reached the 

stage of final attainment. But what is the nature of yagya that is 

performed by worshippers who have just set out on the quest ? So lord krishna says in the next sloka:-

                daivam evapare yajnam, yoginah paryupasate
                brahmagnav apare yajnam, yajnenaivopajuhvati
                                             -B.G. CHAP-4 SLOKA 25
English Translation- “Some yogis perform yagya to foster divine impulses, whereas some other yogis offer the sacrifice of yagya to (a seer who is) the fire of God. ’’


In the last verse Krishn portrayed the sacrifice made by sages who have made their abode in the Supreme Spirit. But he now depicts the yagya performed by worshippers who wish to be initiated into yog. These novices undertake sincere performance of yagya to gods to foster them, that is, they strengthen and augment divine impulses in the heart. Here it is useful to remember how Brahma had directed mankind to foster gods by yagya. The more virtues there are cultivated and garnered in the heart, the more the worshipper advances towards the ultimate excellence until he at last attains it. The novice worshipper’s yagya is thus aimed at strengthening the forces of righteousness in his heart. Other yogis perform yagya by offering sacrifice to the accomplished teacher in his heart-the sacred fire that is an 

embodiment of God.

These other yogi offer oblations to the Godlike teacher who also annihilates evils like fire. They perform sacrifices aimed at this accomplished teacher who is also an embodiment of sacrifice. In brief, they concentrate their minds on the form of the accomplished teacher, a realized sage.



           srotradinindriyany anye, samyamagnisu juhvati
          shabdadin visayan anya, indriyagnisu juhvati 
                                         -B.G. CHAP 4 SLOKA 26
English Translation- “While some offer their hearing and other senses as sacrifice to the fire of self-restraint, others offer speech and other sense objects to the fire of the senses.’’


Yet  other yogi offer all their senses of action-ear, eye, skin, tongue, and nose-to the fire of self-control, that is, they subdue their senses by withdrawing them from their objects. There is no real fire in this case. 

There are then yogi who offer all their senses of perception, sound, touch, form, taste, and smell, to the fire of senses; they sublimate 

their desires and thus turn them into effective means for 

achievement of the supreme goal.

            sarvanindriya-karmani, prana-karmani capare
         atma-samyama-yogagnau, juhvati jnana-dipite
                                           -B.G. CHAP 4 SLOKA 27
English Translation- “Yet other yogi offer the functions of their senses and operations of their life-breaths to the fire of yog (selfcontrol) kindled by knowledge.’’

In a still higher state than this, yogi offer as oblation the 

functions of all senses and operations of life-breaths to the fire of 

yog that is lit up by knowledge of God. When restraint is integrated 

with the Self and the operations of breath and senses are stilled, 

the current which stimulates passions and the current which propels 

one towards God merge into the Self. 

Yogeshwar Krishn again explains yagya :
          dravya-yajnas tapo-yajna, yoga-yajnas tathapare
         svadhyaya-jnana-yajnas ca, yatayah samsita-vratah
                                           -B.G. CHAP 4 SLOKA 28
English Translation - “Just as many perform yagya by making material gifts in service of the world, some other men perform yagya through physical mortification, some perform the sacrifice of yog, and yet others who practise severe austerities perform yagya through the study of scriptures(vedas).’’


There are many who make sacrifice of wealth. They contribute riches to the service of saints. To serve every man, to bring those who have strayed back to the right path, by contributing wealth to the cause is the sacrifice of riches. These sacrifices have the capability to nullify the natural sanskars. Some men mortify their senses through penances for the observance of their dharm. On the basis of this dharm they have been divided into 4 classes Brahman, khatriya baishya and shudra. There are many who practise the yagya of yog. Yog is the joining of the Soul, wandering amidst nature, with God who is beyond nature.
               apane juhvati pranam, prane ’panam tathapare
              pranapana-gati ruddhva, pranayama-parayanah
               apare niyataharah, pranan pranesu juhvati
             sarve ’py ete yajna-vido, yajna-ksapita-kalmasah
                                          -B.G.CHAP4 SLOKA 29-30
English Translation-“As some offer their exhalation to inhalation, others offer their inhaled breath to the exhaled breath, while yet others practise serenity of breath by regulating their incoming and outgoing breath.”“Yet others who subsist on strictly regulated breath and offer their breath to breath, and life to life, are all knowers of yagya, and the sins of all who have known yagya are destroyed.’’


Thus there are many forms of yagna but their result is same to get united with god head. In brief yagna is the act of devotion, act of penance to achive unification with god head...om Tatsat.!