Rigveda 10.5.7
अस॑च्च॒ सच्च॑ पर॒मे व्यो॑म॒न्दक्ष॑स्य॒ जन्म॒न्नदि॑तेरु॒पस्थे॑ ।अ॒ग्निर्ह॑ नः प्रथम॒जा ऋ॒तस्य॒ पूर्व॒ आयु॑नि वृष॒भश्च॑ धे॒नुः॥
asacca sacca parame vyomandakṣasya janmannaditerupasthe |agnirha naḥ prathamajā ṛtasya pūrva āyuni vṛṣabhaśca dhenuḥ ||
Our plain-language meaning of this verse is waiting for scholar review.
Open in the book