The Frogs and the Well

Two Frogs lived together in a marsh. But one hot summer the marsh dried up, and they left it to look for another place to live in: for frogs like damp places if they can get them. By and by they came to a deep well, and one of them looked down into it, and said to the other, "This looks a nice cool place. Let us jump in and settle here."
But the other, who had a wiser head on his shoulders, replied, "Not so fast, my friend. Supposing this well dried up like the marsh, how should we get out again?"

"Look before you leap."