It reached Imam Malik (may Allah have mercy on him) that during the rule of Marwan bin Hakam, people received certificates for the grain of Jar. People sold these certificates to one another before taking possession of the grain. So, Sayyiduna Zayd bin Thabit (may Allah be pleased with him) and another companion (Sayyiduna Abu Hurairah, may Allah be pleased with him) went to Marwan and said: "Do you consider riba (usury) to be permissible, O Marwan?" Marwan said: "God forbid! What are you saying?" They said: "These certificates which people bought, then after buying, sold again before taking the grain." Marwan sent guards to seize the certificates from the people and return them to the certificate holders.