Musnad Abu Ya'la al-Mawsili 153:1

Abu Ya'la Ahmad ibn Ali ibn al-Muthanna informed us, Abu Khaythama Zuhayr ibn Harb narrated to us, Sufyan ibn Uyayna narrated to us, al-Zuhri narrated to us, from Salim, from his father: That the Messenger of Allah (may Allah bless him and grant him peace) forbade the selling of fruit until its ripeness becomes apparent. And he forbade the selling of fruit for dates.