What is the ruling on one who sells merchandise at a price higher than that which was agreed upon, knowing that the buyers are small-scale traders who, in turn, sell it at a higher price? Is this permissible under the pretext of "a profit for me is a profit I benefit for myself"?

It is not permissible for a grocer to raise the price of a specific commodity if he is an agent for the company, as the increase is for the company and not for him. If he buys the commodity at a reduced price due to people's need, or if there is government support to sell it at a suitable price, then he is not allowed to take a profit except what was agreed upon, according to the saying of the Prophet, peace be upon him: "Muslims are bound by their conditions in what is lawful." The purchase by merchants from him and their raising of the price does not justify his breach of the contract, and it is not permissible for him to sell to someone he knows is a merchant who will resell it. Nor is it permissible to violate the condition of the company or the state by not giving the buyer more than his need.