What is the limit of profit in a sale, and is it permissible for a merchant to profit as much as he wishes?

Question:
Honorable Shaykh, may Allah grant you success, he says: Is there a specific profit for the merchant, or is it permissible for him to profit as much as he wishes, even if it is multiplied many times over?

Answer:
Profit follows supply and demand; it rises and falls. The One who sets the price is Allah, as the Prophet (peace and blessings be upon him) said: He said: The One who sets the price is Allah (Glorified and Exalted is He). So this is not in the hands of the people, nor in the hands of the merchants.
This follows supply and demand. If supply is abundant, prices become cheap; if supply is scarce, goods become expensive. No one has any control over this. So if the rise in price is due to that, no one has the right to intervene. But if the rise in price is due to the manipulation of merchants, then the one in authority prevents them from doing so and compels them to sell at the same price as the people.