'Sour Grapes' in the Bible

"In those days they shall say no more, 'The fathers have eaten sour grapes, and the children's teeth are set on edge.'

But everyone shall die for his own iniquity: every man who eats the sour grapes, his teeth shall be set on edge.

"What do you mean, that you use this proverb concerning the land of Israel, saying, 'The fathers have eaten sour grapes, and the children's teeth are set on edge?'