How do we know Jesus' sacrifice was sufficient for our sins?

The sufficiency of Jesus' sacrifice is affirmed through His complete and voluntary acceptance of the cup of wrath on behalf of His people. In Gethsemane, His anguish is evidence of the immense burden of sin He bears. Jesus makes it clear that the cup of suffering cannot pass from Him without completing His mission to atone for the sins of His elect (Matthew 26:39). When He drinks the cup completely, it guarantees that there remains no condemnation for those who believe in Him (Romans 8:1). His sacrifice stands as a perfect fulfillment of divine justice, and God can justly declare the ungodly righteous because Christ has paid the full penalty for their sins.