Tirukkural-On Virtue-Avoiding Idle Talk-Kural 193

The purposeless and profitless meandering talk of a man before a gathering,Will proclaim to the world his own worthlessness.

That is why Benjamin Franklin said,

'The heart of a fool is in his mouth'.

What he utters will set the stamp of worthlessness upon him. No one will have patience with the long-winded and meaningless rantings of such men.

'A fool uttereth all his mind; but a wise man keepeth it in till afterwards'.
(Proverbs 30:11)

'A prudent man conceals his knowledge,
but fools proclaim their folly'.

(Proverbs 12:33)