In plain words
The radiance in the sun that illumines the whole world, and that in the moon and fire—know that radiance to be Mine.
Word for word
The light which, residing in the sun, illumines the whole world, which [is] in the moon and which [is] in fire, that light know [to be] Mine.
यदादित्यगतं तेजो जगद् भासयतेऽखिलम्यच्चन्द्रमसि यच्चाग्नौ तत् तेजो विद्धि मामकम्
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
यत् पदं सर्वस्य अवभासकमपि अग्न्यादित्यादिकं ज्योतिः न अवभासयते, यत् प्राप्ताश्च मुमुक्षवः पुनः संसाराभिमुखाः न निवर्तन्ते, यस्य च पदस्य उपाधिभेदम् अनुविधीयमानाः जीवाः — घटाकाशादयः इव आकाशस्य — अंशाः, तस्य पदस्य सर्वात्मत्वं सर्वव्यवहारास्पदत्वं च विवक्षुः चतुर्भिः श्लोकैः विभूतिसङ्क्षेपमाह भगवान् —
यत् आदित्यगतम् आदित्याश्रयम् । किं तत् ? तेजः दीप्तिः प्रकाशः जगत् भासयते प्रकाशयति अखिलं समस्तम् ; यत् चन्द्रमसि शशभृति तेजः अवभासकं वर्तते, यच्च अग्नौ हुतवहे, तत् तेजः विद्धि विजानीहि मामकं मदीयं मम विष्णोः तत् ज्योतिः । अथवा, आदित्यगतं तेजः चैतन्यात्मकं ज्योतिः, यच्चन्द्रमसि, यच्च अग्नौ वर्तते तत् तेजः विद्धि मामकं मदीयं मम विष्णोः तत् ज्योतिः ॥
ननु स्थावरेषु जङ्गमेषु च तत् समानं चैतन्यात्मकं ज्योतिः । तत्र कथम् इदं विशेषणम् — ‘यदादित्यगतम्’ इत्यादि । नैष दोषः, सत्त्वाधिक्यात् आविस्तरत्वोपपत्तेः । आदित्यादिषु हि सत्त्वं अत्यन्तप्रकाशम् अत्यन्तभास्वरम् ; अतः तत्रैव आविस्तरं ज्योतिः इति तत् विशिष्यते, न तु तत्रैव तत् अधिकमिति । यथा हि श्लोके तुल्येऽपि मुखसंस्थाने न काष्ठकुड्यादौ मुखम् आविर्भवति, आदर्शादौ तु स्वच्छे स्वच्छतरे च तारतम्येन आविर्भवति ; तद्वत् ॥ १२ ॥
In plain words
There is a state that no light can illuminate, not even the brightest light there is, fire, sun, anything, though that very light illuminates everything else. It is the state that, once reached, liberation-seekers never turn back from toward this world again. And it is the state of which every individual soul is a portion, shaped only by the play of its own limiting conditions, the way each pocket of space enclosed in a jar is really just a portion of space itself. Meaning to declare that this state is the very Self of everything, and the ground beneath all our dealings in the world, the Lord now gives, in four verses, a compressed account of his own glory —
'Resting in the sun' means: whatever splendor has the sun as its base. And what is that splendor? Radiance, brightness, the very light that illuminates this whole world, all of it. That same splendor lives in the moon too, the moon that bears the mark of a hare, shining there as light; and it lives in fire, the carrier of every offering. Know that splendor, understand it, as Mine, Mine, belonging to Me, to Me, to Viṣṇu, that is the light spoken of here. Or, taken more deeply: the splendor resting in the sun is really a light of pure consciousness itself, and it is that same light which is present in the moon, and present in fire. Know that splendor too as Mine, Mine, belonging to Me, to Me, to Viṣṇu, that is the light.
But wait, isn't this same light of consciousness equally present in everything that doesn't move and everything that does? So why does the verse single out the sun? This is no real problem: it's because sattva is more abundant there, and greater manifestness naturally follows greater sattva. In the sun and things like it, sattva is at its clearest, its most radiant, so it's only there that the light appears so fully manifest, singled out for that reason, not because there's actually more of it there. Think of the old saying: a face could, in principle, be reflected anywhere, yet no face appears in a plank of wood or a wall, while in a mirror it does appear, more clearly the clearer the mirror is. It is exactly the same here.
Close to the Sanskrit
That state which even a revealer of everything — fire, sun, and the like, [any] light — does not illuminate; which, having attained, liberation-seekers do not, again, facing toward saṃsāra, return [from]; and of which state the jīvas, following the differentiation of its limiting adjuncts, are portions — like pot-spaces are portions of space — [with the] intention of declaring that state's all-Selfhood and its being the basis of all worldly dealing, the Lord states, in four verses, a summary of [his] glories —
That which is 'gone into the sun' [means] having the sun as its support. What is that? Splendor — radiance, light — which illuminates, makes shine, the world, the whole, the entire [world]; that splendor which is in the moon, the hare-bearer, [as] a revealer, exists; and which in fire, the oblation-carrier, [exists] — that splendor, know, understand, [as] Mine, belonging to Me, of Me, of Viṣṇu — that is light. Or alternatively: the splendor resting in the sun is a light of the nature of consciousness; which is in the moon, and which in fire exists — that splendor know as Mine, belonging to Me, of Me, of Viṣṇu — that is light.
Now: in the immovable and in the moving, that same consciousness-natured light is the same. There, how is there this qualification — 'which rests in the sun' etc.? This is not a fault, because of the abundance of sattva, because of the fittingness of its greater manifestness. For indeed, in the sun etc., sattva is of utmost clarity, extremely radiant; therefore, there alone the light, being manifest, is distinguished, but not that it is greater there. As, indeed, in a verse it is said: though the location of a face is equally present, the face does not appear in wood, a wall, etc.; but in a mirror etc., in the clear, in the clearer, by degree, it does appear; just so here. || 12 ||