Our cattle also shall go with us; there shall not an hoof be left behind; for thereof must we take to serve the LORD our God; and we know not with what we must serve the LORD, until we come thither. We know not with what we must serve the Lord, etc. - The law was not yet given; the ordinances concerning the different kinds of sacrifices and offerings not known. What kind and what number of animals God should require to be sacrificed, even Moses himself could not as yet tell. He therefore very properly insists on taking the whole of their herds with them, and not leaving even one hoof behind.
Related Commentaries of Exodus 10:26
Exodus 10:26
26 Our cattle also shall go with us; there shall not an hoof be left behind; for thereof must we take to serve the LORD our God; and we know not with what we must serve the LORD, until we come thither.