What did Jesus pray for at the Last Supper for his disciples?

John chapter 13-17 give a detailed description of what Jesus said during the Last Supper. Matthew, Mark, and Luke do not go into as much detail.

John 14:9 (KJV) Jesus saith unto him, Have I been so long time with you, and yet hast thou not known me, Philip? he that hath seen me hath seen the Father; and how sayest thou then, Shew us the Father?

John 16:5 (KJV) But now I go my way to him that sent me; and none of you asketh me, Whither goest thou?

John 16:19 (KJV) Now Jesus knew that they were desirous to ask him, and said unto them, Do ye inquire among yourselves of that I said, A little while, and ye shall not see me: and again, a little while, and ye shall see me?

John 16:31 (KJV) Jesus answered them, Do ye now believe?