“Abu ‘Abd Allah (a.s.), once said to his son, Muhammad, ‘Son, how much is left with you of that (money) for expenses?’ He replied, ‘Forty dinars are left.’ He said, ‘You should go out and give it away as charity.’ The son said, ‘No more money is left with me besides this.’ The Imam said, ‘You should give it as charity, Allah, the Most Majestic, the Most Glorious, will replace it. Have you not noted that for everything there is a key, and the key to greater means of sustenance is giving charity, so give it as charity.’ The son followed the instruction. Abu ‘Abd Allah (a.s.), waited for only ten days until he received four thousand dinars from a certain place. He then said, ‘Son, we gave Allah forty dinars and He has given us four thousand dinars.’”