How do we know that Jesus succeeded in His mission to save?

The assurance of Jesus' success in His mission to save is rooted in the entirety of His life and ministry, culminating in His atoning sacrifice on the cross. The scriptures affirm that He came to seek and save the lost (Luke 19:10), and His successful completion of this task is echoed in His statement, 'It is finished' (John 19:30), marking the accomplishment of salvation for His people. Additionally, the certainty of salvation is found in the sovereignty of God, as decreed in the covenant of grace that confirms all whom Christ died for will indeed be redeemed. The evidence of His successful mission is further reflected in the transforming experiences of believers who testify to His saving power and presence in their lives.