"This picture, which means little or nothing to our minds, was full of beauty to those who first heard it spoken. Pitchers and jars of earthenware are the usual means of carrying water from the well to the home. These jars are very easily broken. A woman stumbles or falls on her way to the well, the vessel crashes from her head to the ground and there lies in pieces.
Frugality is one of the Eastern woman’s virtues. Even these broken pieces of pottery (sherds) may be turned to service. She selects two of the largest: one she places by the side of the well or water pit; the other she takes home and places beneath the hearth. The piece by the well side will serve some day for the thirsty traveler to stoop down and scoop up the cool waters out of the pit. The sherd by the hearth will be used to carry glowing embers to light another fire, perhaps in a neighbor’s home.
Now we see the full vividness and force of Isaiah’s analogy, which depicts the utter ruin of rebellious and faithless Israel. "
(Bowen, Barbara M., Strange Scriptures that Perplex the Western Mind, WM B. Eerdmans Publishing Co., Grand Rapids, Michigan, 1944, pgs 56-57)