The Prophet ﷺ said, "Do not combine dates with Zabib, nor unripe dates with ripe dates."
أخبرنا سويد بن نصر قال أنبأنا عبد الله عن الأوزاعي قال حدثني يحيى بن أبي كثير قال
عن النبي ﷺ قال لا تجمعوا بين التمر والزبيب ولا بين الزهو والرطب
Bukhari transmitted it, in the Book of Drinks, the chapter on whoever held that unripe and ripe dates should not be mixed, etc., hadith no. 5602, and Muslim, in the Book of Drinks, the chapter on the disapproval of soaking dates and raisins mixed together, hadith no. 1988, from the hadith of Yahya bin Abu Kathir with the same chain, and it is also in Kubra, hadith no. 5060.