Are the profits earned from an investment certificate transferred from an Islamic bank to a conventional bank considered unlawful (haram), and is it obligatory to withdraw the principal amount and leave the profits generated from both banks?

It is permissible to take profits from Islamic banks if the funds are invested in legitimate Mudarabah (partnership) or permissible stocks, unlike the forbidden interest from usurious banks. For the investment or Mudarabah to be valid, it is stipulated that: the bank invests the funds in permissible activities, that it does not guarantee the principal, and that the profit is specified as a percentage of the profit, not of the principal. Funds must be withdrawn from usurious banks, and the interest disposed of by spending it on the poor and needy.