How do we know that Christ's work on the cross is sufficient for salvation?

The sufficiency of Christ's work on the cross is affirmed throughout the New Testament. In John 19:30, Jesus declares, 'It is finished,' which signifies that all the requirements for the redemption of His people have been met. This includes the complete satisfaction of God's justice through His atoning sacrifice, as articulated in Romans 3:25-26, where it states that God put forward Christ as a propitiation through faith in His blood, to show His righteousness. Additionally, Hebrews 10:10 emphasizes that we have been sanctified through the offering of the body of Jesus Christ once for all. This culminates in the assurance that no further sacrifices are needed, and that His work is completely sufficient for our justification and reconciliation with God, making it clear that salvation is found exclusively in Him.