"It is finished" means that Jesus had accomplished all that God's mission had sent him to do. It did not merely mean that his life was over like, "I'm finished". It was a statement of achievement of purpose - God's purpose to deal with sin and guilt, to defeat all the powers of evil, to bring about the reconciliation of enemies, to defeat death itself, and to accomplish the reconciliation and liberation of the whole creation.
Christopher J. H. WrightWe may legitimately see in the [Old Testament] event, or in the record of it, additional levels of significance in the light of the end of the story – i.e. in the light of Christ
Christopher J. H. WrightPerhaps preachers today need to think about the assumptions that are common in their congregation - the plausibilities and comforting assurances - which may in themselves have biblical truth, but can easily become insurance policies waved around as immunity from any kind of serious evaluation of how we are living, whether we are truly following the Lord Jesus in the way he walked, whether we are doing righteousness and justice as God commanded.
Christopher J. H. Wright