The prophet (The Elder Scrolls 5: Skyrim)

Here is a similar forum:
http://forums.playground.ru/elder_scrolls_5_skyrim/tech/problema_s_prohozhdeniem_kvesta_prorok-783580/

Or try to restart the mission entirely, or start with the last stored.
There is an option to add the Malka is the stone in your inventory ( not yourself ! ) and pick up ... ID: XX003D7D