Bhashya
पुरुष जीवनविशिष्ट कार्यकारणसघात यथाप्रसिद्ध एव, वावशब्डोऽवधारणार्थ , पुरुष एव यज्ञ इत्यर्थ ।तथा हि सामान्यै सपादयति यज्ञत्वम् ।कथम् ? तस्य पुरुषस्य यानि चतुर्विशतिवर्षाण्यायुष , तत्प्रात सवन पुरुषाख्यस्य यज्ञस्य ।केन सामान्येनेति, आह— चतुर्विशत्यक्षरा गायत्री छन्द , गायत्र गायत्रीछन्दस्क हि विधियज्ञस्य प्रात -तृतीयसवनमनुसतनुतेति माह प्राणाना५रुद्राणा मध्ये यज्ञो विलोप्सीयेत्युद्धैव ततएत्यगदो ह भवति ॥ ४ ॥
In plain words
The embodied human being formed of cause and effect is well known; the particle 'vā' serves to emphasize that the person alone is the sacrifice. This is how the text establishes the equivalence. How so? The first twenty-four years of a person's life correspond to the morning pressing of this human sacrifice. Through what common link? The text explains: the Gayatri meter has twenty-four syllables, and because the morning and third pressings share this metric essence, one sustains the ritual continuity. Fearing that the life-sacrifice might be cut short in the midst of the vital breaths and the Rudras, one pulls oneself up from that affliction, attains health, and becomes entirely free from disease.
Close to the Sanskrit
The person as the aggregate of cause and effect qualified by life is just as well known; the word 'vā' is for ascertainment, meaning the person alone is the sacrifice. For thus it accomplishes sacrificeness through commonalities. How? Those twenty-four years of that person's life, that is the morning extraction of the sacrifice named after the person. By what commonality? It says: the Gayatri meter has twenty-four syllables, and having the Gayatri meter, carry out continuously the morning and third extraction of the prescribed sacrifice, it says. Lest the sacrifice among the vital breaths and the Rudras should be destroyed, pulling himself up right from there and attaining health, he indeed becomes free of disease.