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.