TT #103 · Parashas Shoftim · Second Aliyah · Passuk 17:17
And he must not multiply wives for himself, so that his heart not turn away; and he must not greatly multiply silver and gold for himself.
Torah Temimah points to Sanhedrin 21b.
TT lemma: וְכֶסֶף וְזָהָב לֹא יַרְבֶּה לוֹ מְאֹד.
English: ‘And silver and gold he shall not multiply for himself greatly’ – one might have thought even enough to pay the soldiers’ wages; therefore the Torah says ‘greatly.’
Derash limiting excess wealth (Bavli) — the word ‘me’od’ (greatly) permits necessary royal funds while forbidding personal hoarding.
The king may accumulate the silver and gold needed for the functioning of the kingdom, but is forbidden to multiply personal wealth to excess.