Fixing a specific amount of profit in a mudarabah (profit-sharing partnership) with the father's money

The questioner:
He says: Honorable Shaykh, may Allah grant you success, my father gave me one hundred thousand riyals and told me to work with them, and to give him two thousand riyals every month,

The Shaykh:
And upon you be peace.

The questioner:
He gave me one hundred thousand riyals and said to work with them, and to give him two thousand riyals every month. Is this permissible or not? And does the ruling change if the owner of the money is not my father?

The Shaykh:
This is not permissible; fixing the amount is not permissible. But if he said, “Trade with it, and you have half the profit, or a quarter of the profit, less or more,” there is no harm. As for fixing a specific amount, giving me a thousand, a hundred, or ten riyals every month, this is not permissible. Yes, not from your father, nor from anyone else. This is a mudarabah (profit-sharing partnership). Yes.