When Jesus cried "It is finished" from the cross, he had finished what His Father sent Him to do. Therefore, we can can be redeemed. Sin no longer holds us in bondage. We are washed in the blood of the Lamb. Satan is defeated. We can have eternal life. We are sanctified, justified, and have an eternal hope. Jesus willingly stood in my place and laid down his life as the payment for my sins and yours. For every single human who ever lived, when Jesus cried, "It is finished" from the cross, it was for you.
This episode is also available as a blog post: https://wellspringchristianministries.org/it-is-finished/