Withholding the Zakah due on one's money and exploiting it in trade
It is not permissible for you
to hold your Zakah or the Zakah which others authorized you to pay on their behalf after the due time of Zakah. Zakah is due once a Hawl (one lunar year calculated from the time a property reaches the minimum amount upon which Zakah is due) has passed over the money. You must pay it out immediately. Also, it is not permissible for you to indulge in any form of trade with the funds of Zakah, whether it is yours or others'. Rather, you must pay it on the spot to the poor once Zakah is due. So, you must immediately give out from your wealth to the poor the amount of money equal to that which people owe. Then the debt, which people were asked to repay, is yours.May Allah grant us success. May Peace and Blessings of Allah be upon our Prophet Muhammad, his family and his Companions!