One Part Finished, But Lots More To Come!

Christ said, "It is finished" on the cross. "It is finished" was His faith-and-hope confession. I say it was an expression of hope and faith because, at that point, the complete work of our salvation wasn't finished in actuality. The resurrection still needed to happen, as well as the Ascension. He also continually intercedes on our behalf, for our salvation from sin, death, and Hell. 

In a sense, a Christian's experience of salvation isn't really finished until we rise in Christ's own glory from the dead. But Christ on the cross knew, with His perfect, sinless faith, that His death finished the payment part of our redemption. And the payment was essential. It was the key that opened the lock. It was the foundation to everything else that would follow. Christ knew His payment was accepted on high by God the Father so, like a workman setting down his shovel after a long, hard day in the sun, He declared His work-day finished and was satisfied.