When John Locke was confronted by "something" in the first season he described it as that he had "looked into the heart of the island" and what he saw "was beautiful." May not be an exact quote but you remember the scene. How about if that was when Jacob decided that John Locke would be the next island protector? However before he could bring it to fruition Locke had left the island (due to Christian) and ended up dead (due to Ben). Now when Locke's body is brought back, Li'l Bro takes over Locke's appearance as if to say . . . Ha ha Jacob, you wanted him but I got him, neener neener.