Even in your thoughts, do not curse the king,
nor in your bedroom curse the rich,
for a bird of the air will carry your voice,
or some winged creature tell the matter.
I don't know for a fact, but this may be the specific etymology of the colloquialism, "a little birdie told me."
The point being this: don't say about someone what you wouldn't want them to know you said about them. Things have a way of getting back to the source.
But if you will not do so, behold, you have sinned against the LORD, and be sure your sin will find you out.
Even if the natural consequences of gossip do not find you out as stated above in Ecclesiastes, the supernatural consequences will track you down.