Charles Ellicott Commentary Hebrews 10:4

"For it is impossible that the blood of bulls and goats should take away sins." — Hebrews 10:4 (ASV)

This verse explains those that precede. No inconsistency really existed in these sacrifices and this ceremonial system, even though they were so often repeated; for it was impossible that any such sacrifice could really remove sin. The offering was necessary, and it served its purpose; but it could not remove the necessity for another and a better offering.