Whoever says the future is forbidden, you should judge this example and then prohibit or permit.
Ali
He owns a car showroom where the price of one car is 10 thousand dollars.
Ahmed
He does not own a car showroom and understands this field well, and he only has 2000 dollars, which does not allow him to own a showroom. He wants to work in this field because he is skilled at it...
Ahmed decided to go to Ali and contract with him to buy the car valued at 10 thousand dollars and give Ali the 2000 dollars, and the car remains with Ali until Ahmed returns and pays him the remaining amount of 8000 dollars.
Ali agreed to the contract but told Ahmed on one condition. Ahmed asked him what it was. Ali said if its price drops in the market, I will deduct from the 2000 that you provided, and if it's depleted, meaning the car's price reaches 8000 dollars, I will call you to come and add another amount so I can continue to reserve it for you and not sell it. Ahmed said okay... There are assumptions:
Let's assume the car's price dropped to 8000. Ali calls Ahmed to come and add another amount or I sell it for 8000 dollars and the 2000 dollars belong to you, Ahmed, as compensation for my loss. Here, the decision is in Ahmed's hands...
What is the benefit of this system?
Ali
Avoid any loss due to its price drop because he didn't sell it and reserved it for Ahmed, ensuring his right.
Ahmed
He became a car dealer with 2000 dollars and started trading with more than his capital because he can sell the car for 12000 dollars.
The question here is
Where is the prohibition in this transaction? Why do you prohibit things you do not understand? Where is gambling? Where is usury?
It's all nonsense... the future is exactly the same as this example. I, Ahmed, enter with 10 dollars and Ali allows me to trade with a volume of 100 dollars. If it reaches liquidation due to a price drop, I must reinforce like Ahmed so that Ali can ensure he does not lose if its price drops further, in exchange for Ali reserving 100 for Ahmed...