The rituals of all ceremonies for which sacrificial fees are sanctioned, beginning with birth-rite and ending with Sama-vartana (return from preceptor's house) depend for their performance upon a preceptor well-versed in the Vedas.
जातकर्मप्रभृत्यस्य कर्मणां दक्षिणावताम्। क्रिया स्यादासमावृत्तेराचार्ये वेदपारगे॥