In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

Imaam as-Sadi [may Allaah have mercy upon him] said:

What the Sharee’ah brought about the command to prevent a person from spending his wealth if it is harmful to him or someone else, such as preventing the insane person, the young, the foolish and the like, and restraining the debtor’s spending for the sake of safeguarding his creditor: all this is from the excellence (or virtues) of the Sharee’ah, because even though a person is initially given complete freedom to spend his wealth, however if his behavior in this affair becomes more harmful than beneficial, and its evil is greater than its good, Allaah places a restriction on him based on what will be of benefit, as a guidance for people to hasten towards spending in every beneficial thing and not what is harmful. (1) See appendix a

Appendix a: Islam commanded that knowledge of trade and economic matters are learnt, to the extent that it commanded that young orphans are observed, taught how to engage in trade and seek earnings. Allaah [The Exalted] said: [وَٱبۡتَلُواْ ٱلۡيَتَـٰمَىٰ حَتَّىٰٓ إِذَا بَلَغُواْ ٱلنِّكَاحَ فَإِنۡ ءَانَسۡتُم مِّنۡہُمۡ رُشۡدً۬ا فَٱدۡفَعُوٓاْ إِلَيۡہِمۡ أَمۡوَٲلَهُمۡ‌ۖ – And try orphans (as regards their intelligence) until they reach the age of marriage; if then you find sound judgement in them, release their property to them (Surah An-Nisaa Aayah 6)]. Islam did not order that the wealth of the orphans is given to them until the guardian is knows (with certainty) regarding their rationality and their knowledge of the matters related to earning and trade.

Commentary: This is an instruction to the guardian regarding the wealth of an orphan, that the wealth is not left in the hands of the orphan until he (or she) observes and knows the orphan’s mental discernment and good judgement in affairs of wealth. But if it becomes clear to the guardian that the orphan is ignorant regarding buying, selling and how to deal with others, then the wealth would be lost immediately when left under the orphan’s jurisdiction. [From 28mins 32secs to 29mins 50secs. https://www.al-badr.net/detail/3KwCnaB5tN ]

[Ref 1: Ad-Durra Al-Mukhtasar Fee Mahaasin Deen Al-Islaamiy page 30 slightly paraphrased]