'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:

for every one shall die for his own iniquity; every man that eateth the sour grapes, his teeth shall be set on edge.

What mean ye, ye who use this proverb of the land of Israel, saying, The fathers eat sour grapes, and the children's teeth are set on edge?