The officers can make a voluntary contact with him by asking if
they can speak to him. The officer can then ask him any questions
that they want to. They can ask his permission to search him and if
he agrees, they can search. The officers don't know who is a
reverend, and anyway, reverends can be drug users. If the officers
can articulate that the reverend's actions give rise to reasonable
suspicion of drug activity, they can temporarily detain the
reverend. Then, since weapons are known to go hand in hand with
(articulable actions of) drug activity, they can search the
reverend for weapons, and if they come across drugs in that search,
they can arrest.