Bhagavad-Gita: Chapter 3, Verse 12

Rudra Vaisnava Sampradaya:

Visnuswami

Sridhara Swami's Commentary

Lord Krishna reveals the positive results in performing yagna or worship to the devas or demi-gods in receiving prosperity and abundance and the negative results in not first offering what one is about to partake to the demi-gods in reciprocation. Therefore one who enjoys food which was originally placed on Earth by the demi-gods and which mankind uses for their life preservation and sustenance without offering it first to them in yagna or worship is a thief . This is for ordinary people. For duly initiated Brahmins in one of the four authorised disciplic successions the five daily yagnas must be performed as well.

Brahma yagna- Study of the Vedic scriptures

Pitri yagna- Offering vegetarian foods to the anscestors

Deva yagna- Offering of oblations to the demi-gods

Bhuta yagna- Offering blessings to all created being

Nri yagna- Showing hospitality to any guest that comes by

Brahma Vaisnava Sampradaya:

Madhvacarya
There is no commentary for this verse.

Sri Vaisnava Sampradaya:

Ramanuja

Ramanuja's Commentary

The words yagna-bhavitah means honoured by worship. The worship of pleasing the demi-gods in which Lord Krishna also resides as the atma or soul will confer on those whose perform it whatever prosperity and abundance they have prayed for. This means that by receiving these things as such one is able to worship the demi-gods and receive from them perpetually by offerings and worship to them with regularity.

But if one should try to enjoy the gifts granted by them without first offering them back beforehand then such a person is a thief for misappropriating what was not sanctioned by the act of yagna or appeasement. Stena eva sah means one is certainly a thief. A thief is one who executes chaurya or larceny. The definition of larceny is the intention of or act of one to misappropriate property for oneself for the use of which they have no right which factually belongs to others.

Thus to one of this nature and this description there is not only forfeiture and exemption from moksa or liberation from the cycle of birth and death but there will also be suffering for these sins in the infernal regions of the hellish planets described in Canto V of the Bhagavat Purana. This same subject is further explained in the next verse .

Kumara Vaisnava Sampradaya:

Nimbaditya

Kesava Kasmiri's Commentary

Evaluating the previous verse Lord Krishna points out the offense in not performing yagna or worship and first offering of the fruits of yagna.before enjoying them. One who enjoys before first offering worship and appeasement and prayers is undoubtedly a thief and will be punished like a thief at the end of their life by Yamaraja the minister of death.