How do we know Christ's sacrifice is the only thing accepted by God?

The acceptance of Christ's sacrifice is affirmed in Scriptures such as Hebrews 10, where it states that God takes pleasure not in the sacrifices of the law but in the body prepared for Christ to offer. His death on the cross was the definitive and final sacrifice that redeemed God's elect, as affirmed by the phrase 'It is finished' which signifies the complete fulfillment of God's plan for redemption. Thus, there is no other means by which we can be accepted; it is only through Christ's sacrificial death that we stand justified before God.