How can we know that Christ's sacrifice was sufficient for salvation?

The sufficiency of Christ's sacrifice is founded in the doctrine of justification. When Christ died, He bore the full wrath of God, satisfying justice and fulfilling all the law's demands. Romans 5:10 confirms that we were reconciled to God through His death, ensuring that for those for whom Christ died, salvation is fully secured. This means that the law cannot condemn those who are in Christ, as their sins have been taken away and replaced with His righteousness. Thus, our faith rests solely on His completed work, which is the foundation of our assurance in salvation.