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

Scripture emphasizes that Jesus' sacrifice on the cross and His subsequent resurrection fully accomplished the redemption of His people. For instance, in Colossians 2, it states that through Christ's death, He 'blotted out the handwriting of ordinances that was against us' (Colossians 2:14), signifying that no additional work is necessary for salvation. Believers are reminded that their sins are forgiven and have been taken out of the way. The completeness of Christ's work is validated by His resurrection, which serves as God's affirmation that His sacrifice was accepted. Hence, believers can have full assurance that in Christ, their salvation is secure and sufficient.