What does the Bible say about the work of Christ being finished?

When Christ said 'It is finished,' He confirmed that He completed all the tasks He was sent to accomplish on earth, including establishing a perfect righteousness, atoning for sin, and fulfilling the law. This declaration signifies that nothing remains for sinners to do in terms of earning salvation; it is entirely the work of Christ. Every detail of His mission, from His incarnation to His sacrificial death and resurrection, was fully essential for the redemption of God’s elect, encapsulated in the themes found in Romans 8:28-30 and Ephesians 1:4-5. Thus, believers can rest in the assurance that their salvation is secure in the finished work of Christ.