Jabir b. 'Abdullah al-Ansari reported that Messenger of Allah ﷺ prohibited the (preparation of) Nabidh by mixing together fresh dates and grapes, and he prohibited the preparation of Nabidh by mixing the fresh dates and unripe dates together. (Using translation from Muslim 1986b)
نَهَى رَسُولُ اللهِ ﷺ أَنْ يُنْبَذَ التَّمْرُ وَالزَّبِيبُ جَمِيعًا وَأَنْ يُنْبَذَ التَّمْرُ وَالْبُسْرُ جَمِيعًا