How do we know Christ's work of redemption is complete?

Christ's declaration 'It is finished' on the cross signifies the completion of His redemptive work, fulfilling the legal demands of God for salvation (John 19:30). This command shows that He accomplished everything required for atonement, including bearing the sins of the elect and enduring the corresponding wrath of God. Furthermore, the resurrection serves as the Father's affirmation that Christ's work was not only completed but also accepted. Thus, those redeemed by Christ's blood are guaranteed forgiveness of their sins and eternal life, as evidenced throughout Scripture.