The king is instructed not to get for himself too many horses, too many wives, or too much wealth: Only let him not get himself many horses, that he not turn the people back to Egypt in order to get many horses…And let him not get himself many wives, that his heart not swerve, and let him not get himself too much silver and gold. Whereas the Torah explains the dangers of a king acquiring too many horses (that he not turn the people back to Egypt) and too many wives (that his heart not swerve), it offers no explanation for why the king is banned from acquiring too much silver and gold. This shows, R. Hirsch explains, that of all the weaknesses for a ruler to have, the wish to acquire wealth is the most dangerous; the Torah simply prohibits it without entertaining any explanation.