How Close is Close?

As I think about the closeness of the members of the Trinity, I realize I can never have a human relationship that is as close as the Trinity has within itself.

But I wonder how close is close? When I try to think about the closeness, the thought that pops into my mind first is separation:

At the ninth hour Jesus cried out with a loud voice, "ELOI, ELOI, LAMA SABACHTHANI?" which is translated, "MY GOD, MY GOD, WHY HAVE YOU FORSAKEN ME?"
Mark 15:34 (NASB)

This is a cry of a man who feels the full, complete and total separation from God, that crushing feeling awaiting all who do not turn to Jesus and place their faith and trust in Him alone as Savior. It is a feeling none of us have experienced and by the grace of God never will. But it is a complete separation for Jesus as a man of the unity He feels within the Trinity as God.

William Young, in his book The Shack, has an incident where the main character in a discussion with God the Father notices the scars of crucifixion on His wrists, scars also borne by the Son. This is a picture that does not sit well with me for in my mind for it negates for me that separation from the Father that proved incredibly painful for the Son to bear. It intimates a sharing of the physical pain, a closeness that I believe needed to be broken on the Cross in order for Christ's sacrifice to be completed. This passage in the book, along with the Scripture verse above, paint the picture of defining closeness by the pain separation brings about.

What are your views of the closeness of the Trinity? Are there other Scripture verses called to mind as you think abouyt that closeness? Are there other books you have read that touch upon that topic for you?

I would love to hear your thoughts.