"It is done"

According the Christian New Testament, the fellow named Jesus is said to say this verse that "it is done" upon the end of his crucifixion on the cross.  This is quite a startling revelation considering that Mr. Jesus is told to us to be "god in the flesh and blood".  To say that "it is done" marks that your work is completely finished.  If this Mr. Jesus was our G-d which I will tell you clearly he is not, it would indicate that G-ds work was done on this planet.   This strikes me as asinine as clearly the work of G-ds creation is everlasting and goes on and on.  When I finished writing a book, I never say "it is done".  I say "I have completed my writing". There is a marked difference.  For me to say that "it is done" might indicate that this work has no further use in my life or in the purpose of the work of our Creator.  There is nothing that is "done and complete" in the universe when it comes to making a philosophical statement or an endeavor of intelligent aperture.  So I would have to say that this idea that G-ds work is "done" by Mr. Jesus's time on the cross is just plain silliness at best.  Sorry to all my devout christian friends.  I can not indeed be a part of a silly situation of sillyness and silly ideas.  Thanks.