How do we know Christ's sacrifice was sufficient for our salvation?

We know that Christ’s sacrifice was sufficient for our salvation because He perfectly fulfilled the role of a substitute as outlined in Scripture. Isaiah 53:6 states, 'the Lord has laid on Him the iniquity of us all,' indicating that Christ bore the sins of His people, satisfying God’s justice. Furthermore, in 2 Corinthians 5:21, 'For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God,' it shows that Jesus took upon Himself not only the guilt of our sins but also granted us His righteousness. Therefore, through His sacrificial death and subsequent resurrection, we have a complete and perfect atonement for our sins, affirming the Reformed doctrine of justification by faith alone in Christ alone.