Bhashya
तस्मात् पुरुषात् ऋच नियताक्षरपादावसाना गायत्र्यादिच्छन्दोविशिष्टा मन्त्रा , साम पाञ्चभक्तिक साप्तभक्तिक च स्तोभादिगीतिविशिष्टम् , यजूंषि अनियताक्षरपादावसानानि वाक्यरूपाणि , एव त्रिविधा मन्त्रा ।दीक्षा मौञ्ज्यादिलक्षणा कर्तृनियमविशेषा ।यज्ञाश्च सर्वे अग्निहोत्रादय ।
In plain words
From that supreme Purusha come the Rigvedic hymns, structured with precise syllables, metrical feet, and endings, and set to sacred meters like the Gayatri. From Him come the Samavedic chants, sung in five-fold or seven-fold melodies with their musical interjections. From Him come the Yajurvedic prose formulas, unbound by metrical feet or syllable counts, flowing as sacred sentences. These are the three kinds of mantras. From Him also come the initiations—marked by the wearing of the Munja grass girdle and other sacred vows—which bind the performer to disciplined restraint. And from Him arise all the ritual sacrifices, beginning with the daily fire-offering.
Close to the Sanskrit
From that Purusha [originate] the Rigvedic verses, which are characterized by a fixed number of syllables, feet, and endings, and are distinguished by meters such as Gayatri; the Samavedic chants, which are five-fold or seven-fold and are characterized by musical interjections and singing; the Yajurvedic formulas, which do not have a fixed number of syllables, feet, or endings, and are in the form of prose sentences; thus are the three kinds of mantras. Initiation is characterized by the wearing of Munja grass and the like, consisting of specific restrictive rules for the performer. And all the sacrifices, beginning with the Agnihotra.