Bhashya
ब्रह्मणो हृदयाद्यनेकोपाधिविशिष्टस्य उपासनमुक्तम् ; अथइदानीं गायत्र्युपाधिविशिष्टस्य उपासनं वक्तव्यमित्यारभ्यते ।सर्वच्छन्दसां हि गायत्रीच्छन्दः प्रधानभूतम्; तत्प्रयोक्तृगय-त्राणात् गायत्रीति वक्ष्यति ; न च अन्येषां छन्दसां प्रयो-क्तृप्राणत्राणसामर्थ्यम् ; प्राणात्मभूता च सा ; सर्वच्छन्दसांच आत्मा प्राणः ; प्राणश्च क्षतत्राणात् क्षत्रमित्युक्तम् ; प्राण-श्च गायत्री ; तस्मात् तदुपासनमेव विधित्स्यते ; द्विजोत्तम-जन्महेतुत्वाच्च- 'गायत्र्या ब्राह्मणमसृजत त्रिष्टुभा राजन्यंजगत्या वैश्यम्' इति द्विजोत्तमस्य द्वितीयं जन्म गायत्रीनि-मित्तम् ; तस्मात् प्रधाना गायत्री ; 'ब्राह्मणा व्युत्थाय ब्राह्मणाअभिवदन्ति, स ब्राह्मणो विपापो विरजोऽविचिकित्सो ब्राह्मणोभवति ' इत्युत्तमपुरुषार्थसंबन्धं ब्राह्मणस्य दर्शयति , तच्च ब्रा-ह्मणत्वं गायत्रीजन्ममूलम् ; अतो वक्तव्यं गायत्र्याः सत-त्त्वम् ।गायत्र्या हि यः सृष्टो द्विजोत्तमः निरङ्कुश एवउत्तमपुरुषार्थसाधने अधिक्रियते ; अतः तन्मूलः परमपुरुषा-र्थसंबन्धः ।तस्मात् तदुपासनविधानाय आह — भूमिर-न्तरिक्षं द्यौरित्येतानि अष्टावक्षराणि ; अष्टाक्षरम् अष्टावक्ष-राणि यस्य तत् इदमष्टाक्षरम् ; ह वै प्रसिद्धायद्योतकौ ; एकंप्रथमम् , गायत्र्यै गायत्र्याः , पदम् ; यकारेणैव अष्टत्वपूर-णम् ।एतत् उ ह एव एतदेव अस्या गायत्र्याः पदं पादःप्रथमः भूम्यादिलक्षणः त्रैलोक्यात्मा , अष्टाक्षरत्वसामान्यात् ।एवम् एतत् त्रैलोक्यात्मकं गायत्र्याः प्रथमं पदं यो वेद ,तस्यैतत्फलम् — स विद्वान् यावत्किंचित् एषु त्रिषु लोकेषुजेतव्यम् , तावत्सर्वं ह जयति , यः अस्यै एतदेवं पदं वेद ॥
In plain words
The meditation on Brahman as the heart, and under its many other guises, has already been taught. Now a new one begins: meditation on that same Brahman as the Gāyatrī. Of all the Vedic meters, Gāyatrī stands first — because, as will be shown, it protects the very breath of whoever sings it; that is where its name comes from. No other meter can do that for the one who recites it. Gāyatrī, in truth, is nothing but breath itself, and breath is the living core of every meter there is. And breath — remember — was already shown to be called Kṣatra, because it protects a wound; that same breath is Gāyatrī. So this one meditation, on breath as Gāyatrī, is really the whole point being taught here. There is another reason Gāyatrī matters so much: it gives the finest of the twice-born their second birth — 'Through Gāyatrī he created the brahmin, through Triṣṭubh the warrior, through Jagatī the merchant.' That second birth, the one that makes someone a brahmin, comes from Gāyatrī — which is why Gāyatrī stands first among the meters. And there is a saying: 'When brahmins rise up and speak as brahmins, such a one becomes free of sin, free of taint, free of doubt — a true brahmin.' That saying ties the very highest human goal to being a brahmin, and being a brahmin is rooted in the birth Gāyatrī gives. So it is worth explaining exactly what Gāyatrī truly is. Whoever is born through Gāyatrī, the finest of the twice-born, stands unrestrained, fully qualified to pursue the highest ends a person can pursue — and it is that very root that connects him all the way to the ultimate human goal. So, to teach how to meditate on Gāyatrī, the text now says: 'Earth, the space between, sky' — count them and you get eight syllables. Eight-syllabled simply means having eight syllables, and that is exactly what this is. 'Ha' and 'vai' are just familiar little words used for emphasis. 'One' means the first foot; 'of Gāyatrī' tells you whose it is; 'foot' tells you what it is — one quarter of the whole verse. This very thing — earth, sky, and the space between — is this first foot of the Gāyatrī, sharing the same eight-syllable count as her other feet and carrying within it the nature of all three worlds. Know this first foot of Gāyatrī, carrying the nature of the three worlds, and here is what you gain: you win everything there is to win, in every one of these three worlds — you, the one who knows this foot of hers in just this way.
Close to the Sanskrit
The meditation on Brahman, characterized by many limiting adjuncts beginning with the heart, has been stated. Now, at this point, the meditation on that characterized by the adjunct of Gāyatrī is begun, to be described. For the Gāyatrī meter is indeed the foremost among all the meters; hence, from protecting its reciter who sings it, it will be explained, it is called Gāyatrī. And the other meters do not have the capacity to protect the breath of their reciter. And she is essentially of the nature of breath. And breath is the self of all the meters. And breath, from protecting a wound, was called Kṣatra, as already stated. And breath is Gāyatrī. Therefore, the meditation on that alone is intended to be enjoined. And also because it is the cause of the second birth of the best of the twice-born — 'through Gāyatrī he created the brahmin, through Triṣṭubh the kṣatriya, through Jagatī the vaiśya' — thus the second birth of the best of the twice-born has Gāyatrī as its cause; therefore Gāyatrī is foremost. 'Brahmins having risen up, brahmins proclaim — that brahmin becomes free from sin, free from taint, free from doubt, a true brahmin' — this shows the connection of the highest human goal with brahminhood; and that state of brahminhood is rooted in the birth Gāyatrī causes. Therefore the true nature of Gāyatrī is to be explained. For the best of the twice-born, born through Gāyatrī, unrestrained indeed, becomes qualified for the pursuit of the highest human goals; therefore, rooted in that, is the connection with the supreme human goal. Therefore, for the sake of prescribing meditation on that, he says — 'Earth, mid-space, sky' — these are eight syllables. Eight-syllabled [means] that of which the syllables are eight — this is that eight-syllabled one. 'Ha' and 'vai' are well-known markers of emphasis. 'One' means 'first'; 'for Gāyatrī' means 'of Gāyatrī'; 'foot' [names the unit meant]. By the letter 'y' alone, the completion of the eight-fold count is achieved. This very thing, indeed, is this foot, this quarter, of this Gāyatrī, the first, characterized by earth and the rest, having the nature of the three worlds, on account of a shared eight-syllable count. Thus, he who knows this first foot of Gāyatrī, having the nature of the three worlds — this is his fruit: that knower wins, indeed, everything whatever there is to be won in these three worlds, he who knows this foot of hers in this way.