'Sour' 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 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, that ye use this proverb concerning the land of Israel, saying, The fathers have eaten sour grapes, and the children's teeth are set on edge?

Their drink is become sour; they play the harlot continually; her rulers dearly love shame.