Musnad Ahmad 27:588

Muhammad ibn Ja‘far and Hajjaj narrated to us, they said: Shu‘bah narrated to us—the meaning is the same—Hajjaj said: From Jabalah, and Ibn Ja‘far said: I heard Jabalah say: Ibn al-Zubayr used to provide us with dates. He said: The people had been afflicted with hardship at that time. We would be eating, and Ibn ‘Umar would pass by us while we were eating, and he would say: "Do not practice *iqran* (pairing dates), for the Messenger of Allah (ﷺ) forbade *iqran*." Hajjaj said: "He forbade *iqran* unless a man asks his brother for permission." And Shu‘bah said: "I do not see this phrase regarding asking for permission as being anything other than the words of Ibn ‘Umar."