Gita 3.13

Gita 3.13. . .(1)

यज्ञशिष्टाशिनः सन्तो 

मुच्यन्ते  सर्वकिल्बिषैः  |

भुन्जते ते त्वघं पापा ये पचंत्यात्मकारणात ||

'The good people, living on the remnants of yajna (यज्ञ), are freed from all sins; but those, on the other hand, who cook food (only) for themselves eat only sin.'

Whatever you eat after a sacrifice is called yajnashishta (यज्ञशिष्ट), the remnant of a yajna (यज्ञ). 

This yajnashishta (यज्ञशिष्ट) is also called prasaad (प्रसाद). 

Whatever is a prasaad (प्रसाद) is holy food; what is not prasaad (प्रसाद) has no elevating power for the human system. 

In the social context, you earn, you pay your taxes, what remains is your wealth to enjoy; by trying to avoid paying taxes through all sorts of tricks, society suffers; you also suffer. 

This idea we have to imprint upon the mind of everyone, that you can't get peaceful social order without paying for it. Tax is what we pay for making a stable society. 

Those who avoid paying taxes, and adopt all sorts of tricks for it, they are not citizens, they are only IN the nation, but not OF the nation, and not FOR the nation; they are not fit to live in an ordered society. 

They are fit to have a life of their own separately in some unpopulated island; but then, without human company, they will not often develop humanness.

 Kilbisha (किल्बिषा) means sin and evil.  

Then comes the statement: Bhunjate te tvagham pap ye pachanti atmakaranaat (भुन्जते ते त्वघं पाप ये पचन्ति आत्मकारणात). 

This is a very profound idea. 'One who cooks only for oneself (and eats separately without caring for others), eats only that much sin.'That is the language. 

Agham (अघम) means sin; pap (पाप) also means sin; ye pachanti (ये पचन्ति), 'those who cook'; atmakaranaat (आत्मकारणात), 'only for oneself'. 

I am cooking only for myself; I don't care for others. 

That attitude is extremely bad. Therefore, very often, in our traditional Hindu houses, they follow what is called bhuta-yajna (भूत-यज्ञ), the setting apart of a small portion of food after the cooking is over. 

That is given to any beggar, or birds. They keep it separate; only the rest they utilize. The idea behind it is what this verse expresses. 

In the Gita, the Mahabharata, and the Manu-Smriti this idea is expressed:

 Agham tu kevalam bhunkte ye pachanti atmakaranaat (अघम तु केवलम भुंक्ते ये पचन्ति आत्मकारणात). 'one who cooks for oneself, eats only that much sin'. 

That self-centredness is not appreciated at all. So, this is one important idea. Don't eat sin; eat virtue; 

FOOD BECOMES VIRTUE WHEN IT BECOMES A PRASAD (प्रसाद). You have given something to other people and you used for yourself what remained; that is beautiful. 

The yajna (यज्ञ) value is manifested there. This very teaching is given also by Isa Upanishad's (इशोपनिषद) first verse: tena tyktena bhunjitha (तेन त्यक्तेना भुन्जीथा), 'ENJOY LIFE THROUGH RENUNCIATION'. 

Then only you get the best of life. You care only for your own life; by that you will never enjoy the best of life.  So, in verses 14 and 15, you find mention of Chakram (चक्रम्) or ‘wheel of chain of life’.    

Source: 'Universal Message of the Bhagavad-Gita', Pub. Advaita Ashrama, Vol. 1, pp. 273-274)