I Commit My Spirit: What is biblical truth?

I once spend four hours in the middle of the night with a man who was dying from COPD.  A nurse had called me so that he would not die alone.  I heard his last words.  We look at the final words of Jesus as he was dying, which vary from Gospel to Gospel - significantly.  We consider this: Were some of the Gospel authors wrong about Jesus' last words on the cross?  Or were their goals something other than the obvious?  Were they trying to communicate some greater truth?  We consider the bigger issue: what do we mean when we say that the Bible is indeed the truth?