Jabir b. 'Abdullah al-Ansari reported that Messenger of Allah (may peace upon him) prohibited the mixing of grapes and fresh dates, and dry dates and fresh dates. (Using translation from Muslim 1986a)
أَنَّ نَبِيَّ اللهِ ﷺ نَهَى عَنْ خَلِيطِ الزَّبِيبِ وَالتَّمْرِ وَالْبُسْرِ وَالتَّمْرِ