The Rabi, preacher and Imam were fishing and not having much luck and the Rabi picks up his pole and walks about 30-feet or so away from port side of the boat, drops his line and starts landing fish. Then the preacher does the same from the starboard side and starts catching fish.
The Imam, thinking "if their faith is that strong, so is mine and steps off of the boat's stern and immediately sinks out of sight. He bobbed back up and climbed back in a very dejected and crestfallen believer.
The other two return to the boat and drop their fish and go back out into the middle of the lake and start fishing standing on the water. The Imam, not to be denied steps across the bow and again sinks. As he is pulling himself back aboard feeling really rejected by Allah the Rabi calls across to the preacher and says;
"Will you please tell this fool where the rocks are before he drowns himself."
One can see the punch line coming I suppose, but there 'tis.