Sayyiduna Anas bin Malik (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) forbade selling fruit before it ripens. It was said: "O Messenger of Allah (peace and blessings be upon him)! What is its ripening?" He (peace and blessings be upon him) said: "That it turns red." And the Messenger of Allah (peace and blessings be upon him) said: "What do you think: when Allah Almighty withholds the fruit, then how can you take your brother's wealth?"
(b) Abu al-Tahir, from Ibn Wahb, who narrates from Imam Malik (may Allah have mercy on him): they did not mention the words "O Messenger of Allah", nor the words "and the Messenger of Allah said"; rather both of them said: "A-ra'ayta" (What do you think?). One of them used the words "fa-qila lahu" (so it was said to him), and the other(s) used "qalu" (they said).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10593