The note reads only:
Jack originally refused to read the note, putting it in Locke's casket after he put Christian's shoes on him while in Simon’s Butcher Shop. However, the note was given back to him on the plane by Rupa Krishnavani after it was found by the airline security when they were screening his cargo. Jack eventually read the note after a conversation with Ben where he asked Jack if he blamed himself for Locke's suicide. After reading the note on, the plane encounters turbulence and the plane is engulfed in a flash of white light. Jack then wakes up on the Island.
Shortly after waking up, Jack looks at a fragment of the suicide note in his hand. Only the words “I wish” are legible.