Eliphaz was the first to shoot an arrow at Job. He starts out sounding like he was there for Job. Reminding Job how he had been there for others now it was time for others to be there for him. Then he lets the arrow fly. There is something in your life that God is correcting you for. It is like he had been waiting for years to get some dirt on Job and now he believes there is something that Job needs to confess because of what he is going through.
Job has tore his clothes, shaved his head, is sitting in ashes and covered in boils, surely the first thing he did was to check his heart for any sin that he might of committed. I have so been in Job's position where people have said that I had to have done something for the trial I was going through to happen. That is one way not to bring comfort to anyone while they are going through a trial. It only brings condemnation which is not from God.
When someone makes the choice to point out someone else's sin that person has decided to take on the role of the Holy Spirit. Due to the fact that person chose to play the Holy Spirit the reaction to what that person said will bring the response of condemnation and guilt, whereas if the Holy Spirit had touched that person about the sin then it would lead to conviction and repentance.