“Once a man asked abu ‘Abd Allah (a.s.), ‘If I see something in the hand of a man can I testify that it belongs to him?’ He (the Imam) said, ‘Yes, you can do so.’ The man then said, ‘I can testify that it is in his hand but how can I testify that it belongs to him, perhaps it belongs to someone else ? 5 He (the Imam) asked, ‘Is it lawful to buy it from him?’ The man replied, ‘Yes, it is lawful to buy it from him.’ Abu ‘Abd Allah (a.s.), then said, ‘It perhaps belongs to someone else; then how it becomes lawful for you to buy it from him and how can it become of your belongings? How after taking possession can you say that it belongs to you, you can swear and it would be unlawful to ascribe its ownership to one from whose possession its ownership is transferred to you?’ He (the Imam) said, ‘Had it been as you said, the Muslims could never establish a market.”’