If I were you, I wouldn't. When I was 6, I went to a Sunday school class where the teacher delighted in showing us kids hideous torturous pictures of Christ's agony -- the crown of thorns, the blood through the hands, etc. etc. We were told that God did this out of love for us. I jumped up screaming and ran to the door, sobbing -- if that's the case, I didn't want God to Love me!
I was inconsolable. The reaction I had was so visceral, my parents had to be collected during the service. I've only been inside a Church a couple of times since then. I do not now nor ever will comprehend love=tortuous hideous death.
I don't plan to see the movie, but as I mentioned, I have a soft stomach for violence (haven't seen Braveheart, and had to walk out of Dances With Wolves.)
Let your 6 year old grow up first.