Walk on the water

Three clergymen were sitting in a boat, fishing.

"I'm thirsty," said the first. "I'm gonna go get myself a Coke." So he got out of the boat, walked across the water, and came back with his Coke.

"Ooh, that looks good," said the second and got out of the boat. He walked across the water, got his Coke, and came back.

"You're right," said the third. "I think I'll get one too." He steps out of the boat and sinks like a rock.

"Hey," said the first clergyman to the second, "should we tell him where the rocks are?"