In plain words
I am the Vedic rite, I am yajña, I am the offering to the ancestors, I am the healing herb; I am the mantra, the clarified butter, the fire, and the offering.
Word for word
I [am] the kratu, I the yajña, the svadhā [am] I, I the food of plants; the mantra [am] I, I indeed the clarified butter, I the fire, I the act of offering.
अहं क्रतुरहं यज्ञः स्वधाऽहमहमौषधम्मन्त्रोऽहमहमेवाऽऽज्यमहमग्निरहं हुतम्
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
यदि बहुभिः प्रकारैः उपासते, कथं त्वामेव उपासते इति, अत आह —
अहं क्रतुः श्रौतकर्मभेदः अहमेव । अहं यज्ञः स्मार्तः । किञ्च स्वधा अन्नम् अहम् , पितृभ्यो यत् दीयते । अहम् औषधं सर्वप्राणिभिः यत् अद्यते तत् औषधशब्दशब्दितं व्रीहियवादिसाधारणम् । अथवा स्वधा इति सर्वप्राणिसाधारणम् अन्नम् , औषधम् इति व्याध्युपशमनार्थं भेषजम् । मन्त्रः अहम् , येन पितृभ्यो देवताभ्यश्च हविः दीयते । अहमेव आज्यं हविश्च । अहम् अग्निः, यस्मिन् हूयते हविः सः अग्निः अहम् । अहं हुतं हवनकर्म च ॥ १६ ॥
In plain words
If people worship in so many different ways, how is it that they worship you alone? That is the question — and so he answers:
I am the sacred rite itself — the very kind ordained by śruti, I myself. I am the sacrifice ordained by smṛti. More than that: I am the svadhā, the food offered to the ancestors. I am the nourishment every living creature eats, whatever grain or foodstuff that word points to — rice, barley, all of it. Or, taken another way: the food shared by every creature, and the medicine that eases sickness — both of those, too, are Me. I am the very mantra by which offerings reach the ancestors and the gods. I am the ghee and the oblation itself. I am the fire the offering is poured into — that fire is Me. And I am the pouring itself, the whole act of offering.
Close to the Sanskrit
If by many modes they worship, how do they worship you alone? — thus; therefore he says:
I am the kratu, [that is,] a type of Vedically-ordained rite — I myself. I am the yajña enjoined by smṛti. Moreover, svadhā [is] food — I [am that], which is given to the ancestors. I am the auṣadha which is eaten by all living beings — that [substance] denoted by the word 'auṣadha,' common to rice, barley, and the like. Or alternatively, [the word] 'svadhā' [means] food common to all living beings, [while] 'auṣadha' [means] medicine meant for the alleviation of disease. I am the mantra, by which the oblation is given to the ancestors and to the deities. I alone am the clarified butter and the oblation. I am the fire, in which the oblation is offered — that fire is I. And I am the offering [itself] — the act of oblation.