David Lammy had already said (two weeks ago on Question Time) that he's not going to listen to his constituents but instead listen to his church group and vote against any laws on religious ground. So I do wonder if this is Sir Keir's way of quietly kicking this into the long grass.
Then his constituents need to kick him out - he is there to serve them, not whatever deity he personally believes in. A good proportion of which will not believe in or worship the same deity.