I'm not a Bible scholar, but I have always thought that the translation of John 19:30 in the New World Translation of the Holy Scriptures put it in the best perspective for me:
John 19:30: When, now, He had received the sour wine, Jesus said: "It has been accomplished!" and, bowing his head, He delivered up [His] spirit.
I really like the use if the word "accomplished", as opposed to "finished". To me, it makes the meaning much more profound, and reveals the whole process as being much more deliberate.
Not meaning to pick at nits, just sharing a thought.
JESUS SAID *IT IS FINISHED*
What Jesus said was finished is finished -- but -- "the show is not over yet..." :-)
It's finished but it's not done yet...
Remember all things that are prophesied in the Bible (that's "all things") must be done, and there are quite a few things "not done" there, yet...
Even Jesus, Himself, left out key sections of Scripture, distinguishing what part He was doing now, and what part was to come later one.
So, once again, "It is finished" but "it is not done"... :-)