שׁבר sheber — “fragment, crumb, hence, grain.” בר bar — “pure,” “winnowed,” hence, “corn” (grain).

ש…

And the sons of Israel came to buy [corn] among those that came Either among the Egyptians that came to buy, or among tho…

Jacob saw the grain his neighbors had bought in Egypt and brought home. It is a spur to exertion to see others supplied.