"Once upon a time there was a small city with only a few people in it. A
great king came against it, surrounded it and built huge siegeworks around
it. There lived in that city a poor, wise man who saved the city by his
wisdom. But, when the siege was over, no one remembered that poor man."
Luther, in his commentary on this verse, insists that there's an enduring principle here, and cites as his example, the story of Themistocles, the Athenian soldier and statesman who convinced his fellow Athenians that a powerful navy was needed to protect them against the Persians. During the second Persian invasion under Xerxes I, he commanded the Athenian squadron and through his strategy won the Battle of Salamis, drove the Persian army from Greek soil and saved his city. A few years later fell out of favor, was ostracized by his countrymen and banished from Athens. "Thus, Luther concludes, "Themistocles did much good for his city, but received much ingratitude."
Both stories are ancient examples of the modern cliché that no good deed ever goes unpunished.
The crowd, for some perverse reason, will always prefer proud fools to humble, wise woman and men, and will quickly forget the good that their wisdom has done. No matter. "Wisdom is (still) better than strength" even if "the wisdom of the poor man is despised" (vs. 16). It's better to be a quiet, honest sage who, though forgotten, leaves much good behind, than a swaggering, vociferous fool who, though many applaud him, "destroys much good" (vs. 18).
Accordingly, what matters in the end is not the recognition and gratitude we receive for the work we've done, but the souls of those gentle folk in which we've sown the seeds of righteousness. Put another way: "Wisdom is vindicated by the children she leaves behind." -Luke 7:35
 The Hebrew word here, misken ("poor") means humble or "poor in spirit"
(Cf., its use in Isaiah 66:2).