16 So, because Jesus was doing these things on the Sabbath, the Jewish leaders began to persecute him.  ( The religious leaders were so worried about their own power and tradition that they refused to see their Messiah.)  17 In his defense Jesus said to them, "My Father is always at his work to this very day, and I too am working."18 For this reason they tried all the more to kill him; not only was he breaking the Sabbath, but he was even calling God his own Father, making himself equal with God.

19 Jesus gave them this answer: "Very truly I tell you, the Son can do nothing by himself; he can do only what he sees his Father doing, because whatever the Father does the Son also does.20 For the Father loves the Son and shows him all he does. Yes, and he will show him even greater works than these, so that you will be amazed.21 For just as the Father raises the dead and gives them life, even so the Son gives life to whom he is pleased to give it.22 Moreover, the Father judges no one, but has entrusted all judgment to the Son,23 that all may honor the Son just as they honor the Father. Whoever does not honor the Son does not honor the Father, who sent him.  

So Jesus is very clearly, without any doubt, claiming to be God.  Was He lying?  Was He crazy?  These statements leave no room for the claim that He was just a good man and a wise teacher.  The Trinity - one God in three separate beings, Father, Son, Holy Spirit - is alluded to in Jesus' words.  No one really understands how that can be, but "The Shack" is a fictional account of how the Trinity might work.  It is a tough read since the main character's young daughter is kidnapped, abused, and killed.  His anger, guilt, and distance from God are addressed by a very unconventionally conceived Tri-une God.