Musannaf Ibn Abi Shaybah

Hazrat Saeed bin Musayyib was asked that a man bought a camel, then regretted this transaction, so he returns the camel and also gives eight dirhams along with it. How is this? Hazrat Saeed replied that there is no harm in this; usury occurs in those things which are measured by volume or weight, or when they are eaten or drunk.