इष्टान्भोगान्हि वो देवा दास्यन्ते यज्ञभाविताः।
तैर्दत्तानप्रदायैभ्यो यो भुङ्क्ते स्तेन एव सः।।3.12।।
3.12 Being nourished by sacrifices, the gods will indeed give you the coveted enjoyments. He is certainly a theif who enjoys what have been given by them without offering (these) to them.
3.12 Pleased by the sacrifice, i.e., propitiated by the sacrifice, the gods, who have Me as their Self, will bestow on you the enjoyments you desire. Whatever objects are desired by persons keen on attaining release, the supreme end of human endeavour, all those will be granted by gods previously worshipped through many sacrifices. That is, whatever is solicited with more and more propitiation, all those enjoyments they will bestow on you. Whoever enjoys the objects of enjoyment granted by them for the purpose of worshipping them, without giving them their due share in return - he is verily a thief. What is called theft is indeed taking what belongs to another as ones own and using it for oneself, when it is really designed for the purpose of another. The purport is that such a person becomes unfit not only for the supreme end of human endeavour, but also will go down towards purgatory (Naraka). Sri Krsna expands the same:
Ishtaan bhogaan hi vo devaa daasyante yajnabhaavitaah; Tair dattaan apradaayaibhyo yo bhungkte stena eva sah.
iṣhṭān—desired; bhogān—necessities of life; hi—certainly; vaḥ—unto you; devāḥ—the celestial gods; dāsyante—will grant; yajña-bhāvitāḥ—satisfied by sacrifice; taiḥ—by them; dattān—things granted; apradāya—without offering; ebhyaḥ—to them; yaḥ—who; bhuṅkte—enjoys; stenaḥ—thieves; eva—verily; saḥ—they
