John Calvin Commentary Isaiah 32:12

"They shall smite upon the breasts for the pleasant fields, for the fruitful vine." — Isaiah 32:12 (ASV)

Mourning over the breasts. This verse is explained in various ways. Some understand it to mean simply that there will be so great a scarcity of provisions that women will lose their milk, and thus the children will “mourn over dry breasts;” which we sometimes see happen when a very great scarcity of provisions occasions leanness.

But the more generally accepted and more appropriate interpretation is to view the word “breasts” as figuratively denoting fields and vineyards, as the Prophet himself declares; for they are justly compared to the breasts of mothers, because, by deriving nourishment from them, we suck the milk or blood of the earth.

He therefore means that there will be a lack of food and nourishment, because the Lord will curse the earth, so that it will yield no fruits. Thus men will sigh over that scarcity, as if over their mother’s “breasts,” from which they formerly received delicious nourishment. This appears to me to be a more natural meaning and to agree best with the context, for it serves to explain what follows about “rich fields and the fruitful vine.”