The 365th prohibition is that a king is forbidden from having too much money for his personal use.
The source of this prohibition is G‑d's statement1 (exalted be He), "He must not accumulate very much silver and gold."
The limit is that he should not have personal wealth beyond the expenses of his royal court and servants. To accumulate wealth for the needs of the Jewish people, however, is allowed.
The reasons for these mitzvos — "He must not have too many horses," "He must not have too many wives," and "He must not accumulate very much silver and gold" — are given in Scripture.2 Since their reason was known it became possible to nullify them, as is well known from the case of Shlomo, [who nullified them] in spite of his exalted level of knowledge and wisdom, and his being, "Yedidy‑ah" [the beloved of G‑d].
Our Sages said3 that this is a lesson to people that if G‑d would reveal the reasons for all the mitzvos, they would find ways to disobey them. If even one who was so great and perfect [i.e., Shlomo] could make the mistake of thinking that he could do the forbidden act and avoid the underlying reason for the prohibition,4 how much moreso the more weakminded masses. Certainly [if they knew the reasons for the mitzvos] they would disregard them by saying, "this was prohibited," or "this was commanded only for such-and-such a reason. I can avoid the reason for which the commandment was given and ignore [the mitzvah itself]." In such a way, the entire Torah could be nullified. G‑d therefore concealed their rationale.
There is not a single mitzvah, however, that does not have a reason and purpose. The majority of these causes and reasons, though, cannot be grasped or understood by the masses. But regarding them all the Prophet says,5 "The commandments of G‑d are straight, they make the heart rejoice." And I ask that G‑d, in His Kindness, help me fulfill everything that He has commanded in these [mitzvos], and to keep [me] far away from everything He has prohibited in them.
