Thanks to DarkUFO reader DeLaRox for the following.
A friend of a friend of mine was an extra in the Christian Shepherd funeral scene shot recently.
According to her, a letter is read out during the funeral, written by Christian before he died. It mentions Claire and Jack. More shockingly, though, it talks of Christian's guilt over being involved with Widmore and Mittelwerk.
Roll on the next few episodes..!
Source: DeLaRox@DarkUFO