B.G 3.10, 11, 12, and 13

सह यज्ञाः प्रजाः सृष्ट्वा पुरोवाच प्रजापतिः। अनेन प्रसविष्यध्वमेष वोऽस्त्विष्टकामधुक् ॥१०॥

Previously, the lord of the beings created the beings together with Yajna and said "Prosper by means of Yajna. Let it fulfill your desired wishes."

देवान् भावयताऽनेन ते देवा भावयन्तु वः। परस्परं भावयन्तः श्रेयः परमावाप्स्यथ ॥११॥

Please the gods through Yajna, then those gods will please you. By such mutually benefitting activities, you will obtain the highest good.

इष्टान् भोगान् हि वो देवा दास्यन्ते यज्ञभाविताः। तैर्दत्तानप्रदायैभ्यो यो भुङ्क्ते स्तेन एव सः ॥१२॥

The gods certainly grant wishes and objects of desire in the spirit of Yajna. The one who enjoys such given objects without offering them is certainly a thief.

यज्ञशिष्टाशिनः सन्तो मुच्यन्ते सर्वकिल्बिषैः। भुञ्जते ते त्वघं पापा ये पचन्त्यात्मकारणात्॥१३॥

The righteous who partake the remains of the 'Yajna' are freed from all defects. But, those who cook for selfish needs eat severe sins.

Gīta Bhāshya 3.13

तत्र अर्थवादमाह - सहयज्ञा इति ॥१०-१३॥

Here 'artha-vada' is presented by stating 'sahayajñā' i.e. verses 10 to 13.

Note:
'artha-vada' is the term used to explain sentences that are meant to either praise the stated point of view, or to censure the opposing view.
As already clarified, 'Yajna' is an action done for the sake of the lord, without selfish motive, with equanimity. In this context, even demigods grant desires and wishes to the beings, as an offering to supreme lord, in the spirit of 'Yajna', i.e. anticipating the beings will perform 'Yajna' for their wellbeing. Not doing so amounts to misappropriation. Everyone must engage in the activities for the sake of the lord only as his service. Thus righteous activity undertaken becomes 'Yajna'. Activities undertaken with selfish motive are not 'Yajna', and results in bondage.