Humayd al-Tawil says that Sayyiduna Anas bin Malik (may Allah be pleased with him) was asked about selling fruits, and he said that the Messenger of Allah (peace and blessings be upon him) forbade selling fruits before they ripen. It was said: O Abu Hamzah! What is its ripening? He said: "That it turns red and yellow." He says: "If Allah withholds the fruits, then how will you consider your brother's wealth lawful?"
(b) Sufyan al-Thawri (may Allah have mercy on him) narrates from Humayd that, in answer about the explanation of zahw (ripening), he said: "A-ra'ayta in mana'a Allahu al-thamar" (What do you think, if Allah withholds the fruit?). This is the statement of Sayyiduna Anas bin Malik (may Allah be pleased with him), whereas Imam Malik bin Anas (may Allah have mercy on him) made it the statement of the Prophet (peace and blessings be upon him), and al-Darawardi followed him in that, in the narration of Muhammad bin Abbad from him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10597