Musnad Ahmad 938:97

Muhammad ibn Yazid narrated to us, Sufyan ibn Husayn informed us, from al-Zuhri, from Salim, from Ibn Umar, from the Prophet, peace and blessings of Allah be upon him, who said: "Fruit shall not be sold for fruit, and fruit shall not be sold until its soundness becomes apparent." He said: Zayd ibn Thabit met Abdullah ibn Umar and said: "The Messenger of Allah, peace and blessings of Allah be upon him, granted a concession regarding *'araya*." Sufyan said: "*'Araya* are date palms that used to be gifted to the poor, and they were unable to wait for them [to be harvested], so they would sell them for whatever they wished of their fruit."