Bhashya
भिभवौ स्पर्धा ।कदाचिच्छास्त्रजनितकर्मज्ञानभावनारूपावृत्तिः प्राणानामुद्भवति ।यदा चोद्भवति, तदा दृष्टप्रयोजनाप्रत्यक्षानुमानजनितकर्मज्ञानभावनारूपा तेषामेव प्राणानांवृत्तिरासुर्यभिभूयते ।स देवानां जयः, असुराणां पराजयः ।कदाचित्तद्विपर्ययेण देवानां वृत्तिरभिभूयते, आसुर्या उद्भवः ।सोऽसुराणां जयः, देवानां पराजयः ।एवं देवानां जयेधर्मभूयस्त्वादुत्कर्ष आ प्रजापतित्वप्राप्तेः ।असुरजयेऽधर्मभू-यस्त्वादपकर्ष आ स्थावरत्वप्राप्तेः ।उभयसाम्ये मनुष्यत्व-प्राप्तिः ।त एवं कनीयस्त्वादभिभूयमाना असुरैर्देवा बाहु-ल्यादसुराणां किं कृतवन्त इति, उच्यते— ते देवाः, असु-रैरभिभूयमानाः, ह किल, ऊचुः उक्तवन्तः; कथम्? हन्त!इदानीम्, अस्मिन्यज्ञे ज्योतिष्टोमे, उद्गीथेन उद्गीथकर्मपदा-र्थकर्तृस्वरूपाश्रयेण, अत्ययाम अतिगच्छामः; असुरानभि-भूय स्वं देवभावं शास्त्रप्रकाशितं प्रतिपद्यामहे इत्युक्त-वन्तोऽन्योन्यम् ।उद्गीथकर्मपदार्थकर्तृस्वरूपाश्रयणं च ज्ञान-कर्मभ्याम् ।कर्म वक्ष्यमाणं मन्त्रजपलक्षणम्, विधित्स्यमा-नम्— ‘तदेतानि जपेत्’ इति ।ज्ञानं त्विदमेव निरूप्य-माणम् ॥
In plain words
The play of dominance and subjugation is rivalry. Sometimes a mental state arises in the senses shaped by scriptural knowledge and action. When this happens, the ordinary sensory activity driven by perception and inference is subdued by the demonic tendency. That is the victory of the gods and the defeat of the asuras. At other times, the reverse occurs: the divine state is overpowered by the demonic rising. That is the victory of the asuras and the defeat of the gods. Thus, when the gods win, righteousness abounds, leading to an ascent up to the realm of Prajāpati. When the asuras win, unrighteousness abounds, leading to a descent down to stationary plant life. When both are equal, human birth is attained. Pressed by the greater numbers of the asuras, what did the outnumbered gods do? The text says: Being thus suppressed, the gods said to one another, 'Come, let us cross over the asuras in this Jyotiṣṭoma sacrifice through the Udgītha—resting upon the true nature of its action, object, and agent—and thereby subdue the asuras to reclaim our scripturally revealed divine nature.' This reliance is through both knowledge and action. Action is the muttering of mantras to be prescribed shortly: 'One should mutter these.' Knowledge is what is being explained right here.
Close to the Sanskrit
Domination and suppression constitute rivalry. Sometimes the mental state having the form of meditation on action and knowledge generated by scripture of the vital breaths arises. And when it arises, then the functional state of those very same vital breaths having the form of meditation on action and knowledge generated by direct perception and inference is overpowered by the demonic one. That is the victory of the gods, the defeat of the asuras. Similarly, by the reversal of that, the state of the gods is overpowered, and the arising of the demonic state [takes place]. That is the victory of the asuras, the defeat of the gods. Thus, in the victory of the gods, due to the predominance of righteousness, there is elevation up to the attainment of the state of Prajāpati; in the victory of the asuras, due to the predominance of unrighteousness, there is degradation up to the attainment of the state of immovable objects; in the equality of both, the attainment of the human state. Those gods, thus being overpowered by the asuras due to the smaller number [of the gods] and the plurality of the asuras, what did they do?—it is said: Those gods, being overpowered by the asuras, indeed said: 'Come now, in this sacrifice, in the Jyotiṣṭoma, by means of the Udgītha, relying upon the nature of the action, object, and agent of the Udgītha, let us cross over; overcoming the asuras, let us attain our own divine state illuminated by scripture,' thus speaking to one another. And the reliance upon the nature of the action, object, and agent of the Udgītha is through knowledge and action. Action is that which will be spoken of, characterized by the muttering of mantras, about to be prescribed: 'One should mutter these.' But knowledge is this very same being examined.