Do the actions of the brethren, collecting $150 from eight people, then the first person receiving the amount and bringing seven new people to get a larger sum, with a guarantee of refunding the $150 to those who cannot bring new people, count as gambling or usury of favor (riba al-fadl)? And what is the difference between gambling, investment, and trade?

What a person takes from his colleagues as a loan, which he then returns to them, such as an employee's association, involves no harm.

However, if he does not commit to returning the money, and each person strives to bring in others to obtain money unjustly, then this is considered consuming people's wealth by false means. This is because there is no sale, no gift, and no loan involved, and it is a form of gharar (excessive uncertainty) and maysir (gambling), both of which are forbidden in Islamic law.

The difference between trade and gambling: Trade is a legitimate transaction based on conditions, one of which is the absence of gharar, and it entails both potential profit and loss. Gambling, on the other hand, is based on gharar and involves paying money without receiving a tangible equivalent, with the possibility of losing it or gaining multiples of it by chance. It is forbidden due to its detrimental effects, such as unemployment and animosity.