Why did the price of redemption have to be paid?
The price of redemption had to be paid so that God could get control of fallen man. The blood of Christ paid that price in full, far surpassing the blood of bulls and calves, which only covered Israel's sins and could not accomplish this greater work.
Les explains that the blood of bulls and calves did its work by covering the sins of Israel, but it was nothing compared to the blood of Christ. Over and over, the blood of Christ has paid the price of redemption that had to be paid in order for man, or for God, to get control of fallen man. And He has done it; it has been paid in full. This fits the book of Hebrews' comparison: the earthly tabernacle was good, beautiful, and functional, but it was patterned after something in heaven that is far better.
Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.