Bhagavad Gita Chapter 9, Verse 16

अहं क्रतुरहं यज्ञः स्वधाहमहमौषधम् | मन्त्रोऽहमहमेवाज्यमहमग्निरहं हुतम् ||

ahaṁ kratur ahaṁ yajñaḥ svadhāham aham auṣhadham mantro 'ham aham evājyam aham agnir ahaṁ hutam

I am the ritual, I am the sacrifice, I am the offering to ancestors, I am the medicinal herb. I am the mantra, I am the clarified butter, I am the fire, and I am the offering.

Krishna reveals that He is everything in the ritual: 'Ahaṁ kratur ahaṁ yajñaḥ'—I am (aham) the ritual (kratur), I am (aham) the sacrifice (yajñaḥ). 'Svadhāham aham auṣhadham'—I am (aham) the offering to ancestors (svadhā), I am (aham) the medicinal herb (auṣhadham). 'Mantro 'ham aham evājyam aham agnir ahaṁ hutam'—I am (aham) the mantra (mantraḥ), I am (aham) indeed (eva) the clarified butter (ājyam), I am (aham) the fire (agniḥ), and I am (aham) the offering (hutam). This reveals the Supreme's all-pervasiveness: He is everything in the ritual—the ritual itself, the sacrifice, the offerings, the mantra, the fire. Nothing is separate from Him—everything is Him. This is the Supreme's nature: He is everything, yet He transcends everything. This is the ultimate realization: seeing the Supreme in everything.