It's part of a poem called 'Wiseman and a fool':

It is not news that a fool has spoken out of a wise man;

So pleased that the scholar did not answer anything,

All the more he began to scream shrilly;

At last, exhausted, when he had rested,

Said the wise, lest he be indebted in answer:

"Do you know why the bell is loud? Because inside it is empty."

It rhymes in original.

Glad that you liked it. Thanks for the zap.