Bhagavad Gita, Chapter 9, Verse 16

अहं क्रतुरहं यज्ञः स्वधाहमहमौषधम् । मन्त्रोऽहमहमेवाज्यमहमग्निरहं हुतम्

ahaṃ kraturahaṃ yajñaḥ svadhāhamahamauṣadham | mantro'hamahamevājyamahamagnirahaṃ hutam

Translation

I am kratu, I am yajña, I am svadhā, I am auṣadha, I am mantra, Myself the butter, I am fire, I the act of offering.

— Alladi Mahadeva Sastri

Word meanings

aham

I

kratuḥ

the oblation

aham

I

yajñaḥ

the sacrifice

svadhā

the offering to pitṛs

aham

I

auṣadham

the herb

mantraḥ

the mantra

aham

I

ca

and

eva

even

ājyam

the butter

aham

I

agniḥ

the fire

aham

I

hutam

the burnt-offering

Śaṅkarācārya's commentary

Kratu is a class of Vedic sacrifices. Yajña is the worship enjoined in the Smṛti. Svadhā is the food offered to ancestors (Pitṛs). The auṣadha means plants in general, including rice and barley, eaten by all living beings. Or, svadhā is food in general, and auṣadha is the medical (food) serving to alleviate sickness. I am the mantra, the chant with which the oblation is offered to the Pitṛs and the Devatās. I am the fire into which the offering is poured.