Rig Veda 10.9

तस्माद्यज्ञात्सर्वहुत ऋचः सामानि जज्ञिरे । छन्दांसि जज्ञिरे तस्माद्यजुस्तस्मादजायत ॥

tasmad yajnat sarvahuta richah samani jajnire | chhandamsi jajnire tasmad yajus tasmad ajayata

From that sacrifice, in which everything was offered, the Rig verses and the Sama chants were born. The metres were born from it, and from it the Yajur formulas were born.

उस सर्वहुत यज्ञ से ऋचाएँ और साम उत्पन्न हुए; छन्द उसी से जन्मे, यजुष् भी उसी से उत्पन्न हुआ।