民数記 13:18

את הארץ מה הוא AND SEE THE LAND; WHAT IT IS — There are countries which rear strong people and there are countries which rear weak people; there are such as produce a large population and there are such as produce a small population (Midrash Tanchuma, Sh'lach 6). החזק הוא הרפה WHETHER THEY ARE STRONG OR WEAK — He gave them a sign: if they live in open cities they are strong, since they evidently rely on their own strength, but if they live in fortified cities they are weak (Midrash Tanchuma, Sh'lach 6).

וּרְאִיתֶ֥ם אֶת־הָאָ֖רֶץ מַה־הִ֑וא וְאֶת־הָעָם֙ הַיֹּשֵׁ֣ב עָלֶ֔יהָ הֶחָזָ֥ק הוּא֙ הֲרָפֶ֔ה הַמְעַ֥ט ה֖וּא אִם־רָֽב׃

and see the country, what it is; and the people who dwell in it, whether they are strong or weak, few or many;