((Moses) answered: Lo! He saith: Surely she is a cow unyoked) unfettered; (she plougheth not the soil) she is not subjugated for the ploughing of the soil (nor watereth the tilth) nor for carrying water to irrigate it; (whole) free from any blemish (and without mark) spots or flecks of white. (They said: now thou bringest the Truth) now we know the cow's right description. They looked for it and bought her in exchange for her weight in gold. (So they sacrificed her, though almost they did not) i.e. initially; as it is said because the cow was hugely expensive.