A small city, few people, a great king who comes and builds fortifications — (Ecclesiastes 9:14) describes something small being threatened by something enormous. The rabbis identified the small city as the Garden of Eden, the few people as Adam and Eve, the great king as the serpent.
The serpent built his fortifications by telling Adam and Eve that God had a reason to keep them from the tree: "For God knows that in the day you eat of it your eyes will be opened, and you will be like God, knowing good and evil" (Genesis 3:5). This was not a lie exactly — it was a truth used to sow distrust. The serpent's strategy was to make God's prohibition look like self-protection, as if God were guarding something for Himself rather than protecting Adam and Eve from something dangerous.
The "poor and wise man" who could have saved the city is Adam himself (Ecclesiastes 9:15). He had the wisdom — he had been given dominion over every creature, including the serpent. He had the counsel. But he did not use it. He stood beside his wife and ate. The midrash does not explain why — that silence is the silence of the text itself, which offers no psychological account of Adam's compliance. He had the resources to refuse. He did not refuse. And the small city of Eden was overtaken by its single enemy, not by armies but by a question.