Musannaf Ibn Abi Shayba 13:2630

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from ‘Amr, from Isma’il al-Shaybani, who said: I sold what was in the tops of the palm trees, [stipulating] that if it increased, it was for them, and if it decreased, it was upon them. So I asked Ibn ‘Umar, and he said: The Messenger of Allah (may Allah bless him and grant him peace) forbade that, except that he had granted a concession regarding the *‘araya*.