I actually made this post to bring forth some new evidence that complements ghamidi sahab’s work. I watched that video already btw.
What I found is that I Quran 4:2 and 4:6, it says
4:2
Give orphans their wealth ˹when they reach maturity˺
4:6
Test ˹the competence of˺ the orphans until they reach a marriageable age. Then if you feel they are capable of sound judgment, return their wealth to them.
This connects marriageable age with maturity which is connected particularly with the age when someone can independently manage their wealth.
Also, according to Islamic scholars, the age of maturity is 15/18. Imam Abu hanifa said the age of maturity was 18.
https://fiqh.islamonline.net/en/age-of-maturity-for-boys-and-girls/?amp
The purpose of using the example of an orphan under your care is to say that you have to put this much effort for someone that’s not your “biological” child, then a person will logically put in even more effort to their own children ie making sure they’re mature before marriage and also off course their wealth ie saving money for their “biological” child’s future.
Anyways, what do you think. The Quran clearly prohibits child marriage since a child can’t manage their finance without a guardian and the scholars agree that the age of maturity is not just puberty it’s when they’re mentally mature ie as I said before, when they can handle their finances on their own.
Salam.