'Grain' in the Bible

The people curse him who holds back grain [when the public needs it],But a blessing [from God and man] is upon the head of him who sells it.

Where there are no oxen, the manger is clean,But much revenue [because of good crops] comes by the strength of the ox.

The lips of the wise spread knowledge [sifting it as chaff from the grain];But the hearts of [shortsighted] fools are not so.

A wise king sifts out the wicked [from among the good]And drives the [threshing] wheel over them [to separate the chaff from the grain].

Even though you pound a [hardened, arrogant] fool [who rejects wisdom] in a mortar with a pestle like grain,Yet his foolishness will not leave him.