We need Jesus to be our sacrifice because our sin has left us filthy and the sacrificial system is all about making sinners clean. Thankfully the gospel tells us that as the true High Priest, on the final Day of Atonement, Jesus walked into the heavenly Holy of Holies and offered Himself as the ultimate Lamb of God. Why? To take away the sins of the world. The sacrifices of the Old Testament were unable to take away sins because animals were unfit representatives for sinful humans. However, Jesus was not. He is God—strong enough to pile our filth on His back; yet He is also man—weak enough to die as a substitute for sinners. Jesus sacrifice was such a success that He is seated at the right hand of the father, waiting for enemies' backs to prop up His feet. He has "perfected for all time those who are being sanctified." On the cross, He accomplished both our inner cleansing (purifying our desires) and outer cleansing (paying for our forgiveness). Through faith in Jesus we are made clean.