The ruling on selling an item to the person from whom it was purchased

Question:
He says: Honorable Shaykh, may Allah grant you success, I bought a car from my uncle a year ago, and it is with me now, and I want to sell it to him. Is that permissible, given that I had previously bought it from him?

Answer:
If you have paid the full price, there is no harm. However, if the price was deferred and you have not paid it, then if he takes it for the remaining balance, there is no harm, or if he takes it for the price at which he sold it to you, there is no harm. But if he takes it for less than what he sold it to you for, and he will still demand the deferred price for what he sold, then that is not permissible. Yes.