Skandapurana 5.31.57

5.31.57

tathānyadapi viprārhaṃ karma yajñasamudbhavam..
tatteṣāṃ vacanātsarvaṃ pūrṇaṃ syādapi khaṃḍitam ..
parokṣe vāpi saṃpūrṇaṃ vṛthā saṃjāyate sphuṭam .. 57 ..

as well as any other rite worthy of brahmins born of sacrifice— / all that, even if deficient, becomes complete by their word; / or even if complete, in their absence it clearly becomes useless.