It is one of the most ridiculous things that Muhammad left us with and we still cannot agree on a one single way to fix it. It is called “interest rate”. Banks, investors, or any person would lend you money for any number of reasons and would rightly expect some “thank you” in return. Otherwise, what is their incentive to lend you? In the time of Muhammad, there were many shark loans, people who would charge huge interest in return to lending people money. That is also wrong. But what was Muhammad’s solution? A verse in the Quran that BANS the earning of any interest in lending and asking Muslims instead to make lending “for Allah’s sake” meaning without interest! Muhammad went to an extreme here because he would not allow even if you borrowed food to return the food with any more food! https://sunnah.com/abudawud:3348
Muslims really struggled because there was absolutely no way out. The lending system, a corner stone in any banking system, under Islamic shariah nearly collapsed! If you put your money in the bank, in theory, they are not allowed to charge interest or use the money to make interest! So Islamic scholars engaged in hundreds of permutations to try to fix it. They called the bank “investor” and the interest “income” or borrowing as “giving” and you sign to pay your “zakat” through them. To buy a house, the bank will buy it first to the bank and then sell you the house much more expensive in installments (that is not interest!! 😱) I cannot tell you how many bullshit formulas I have come across. And who is paying the price of this? Ordinary Muslims in the West who end up having to rent paying “shark rent rates” while their counterparts of other faiths own their homes and pay it off on less monthly payments to their banks!
Interest rates is a typical example of what Muhammad set out to do. He set out to change the world, to bring people together from other monotheistic faiths as well and pagans – but he was no real politician, he was no real scientist, he was no real doctor, and he clearly was no real economist!
This video by @abdullahsameerwut really hammers the many issues with Islamic ban on interest rates:
https://youtu.be/Ey_xrnttZto