It was narrated from Anas bin Malik that:the Messenger of Allah forbade selling fruits before they ripen. It was said: "O Messenger of Allah what does ripen mean?" he said: 'when they turn red." And the Messenger of Allah said: "What do you think if Allah withholds the fruits (causes it not to ripen), why would any one of you take his brother's wealth?

English translation · Sunan an-Nasa'i