How do we know that Christ's work on the cross is complete?

When Jesus cried out 'It is finished' from the cross, He was proclaiming that every demand of the law and all the prophecies concerning Him had been fulfilled. This declaration is monumental, as it indicates that nothing more is needed for our salvation. The Greek word used conveys the idea of finality and completeness, meaning Christ's atoning work was perfect and sufficient. As stated in Romans 10:4, 'Christ is the end of the law for righteousness to everyone who believes.' Thus, believers can rest assured that their salvation is secure in the finished work of Christ.