The Messenger of Allah ﷺ forbade soaking unripe dates and ripe dates together to make nabidh.
حدثنا بهز حدثنا همام حدثنا قتادة
أن رسول الله ﷺ نهى أن ينبذ البسر والتمر جميعا
Its isnad is sahih. It is found in Bukhari 10/76, no. 5812 (Fath), Muslim 3/1648, no. 2079, and Abu Dawud 4/51, no. 4060, all in the chapter on clothing, striped garments, and in Nasai 8/203, no. 5315, in the chapter on adornment.