(5) باب كَرَاهَةِ انْتِبَاذِ التَّمْرِ وَالزَّبِيبِ مَخْلُوطَيْنِ
Ibn 'Abbas reported that Allah's Apostle (ﷺ) forbade the mixing of dates and grapes together, and mixing of unripe dates and ripe dates together (for preparing Nabidh), and he wrote to the people of Jurash (in Yemen) forbidding them to prepare the mixture of dates and grapes.
Reference: Sahih Muslim 1990 a
In-book reference: Book 36, Hadith 36
USC-MSA web (English) reference(deprecated numbering scheme): Book 23, Hadith 4910