OK, gotta withdraw my suggestion. I’ve since read that he outed himself.
My bad, jumped the shark.
Piytar, I think you were right the first time. As StarT says, it was well known that this man became a Christian. But it was NOT well known that he was Shin Bet agent. This is quite a revelation ... and perhaps puts a political spin on the religious story.
Of course, maybe the Shin Bet story comes out in the book. In that case, he is happy to have it known. Otherwise, no.