Sunan an-Nasa'i, Volume 6, Book 51, Hadith 5558 (DarusSalam) ⓘ
It was narrated from Jabir that: The Messenger of Allah [SAW] forbade soaking raisins and dried dates together, and he forbade soaking Al-Busr and dried dates together.
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ عَطَاءٍ، عَنْ جَابِرٍ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ نَهَى أَنْ يُنْبَذَ الزَّبِيبُ وَالتَّمْرُ جَمِيعًا وَنَهَى أَنْ يُنْبَذَ الْبُسْرُ وَالتَّمْرُ جَمِيعًا.
also referenced under: Hadith 5556 (Reference) & Book 51, Hadith 17 (In-Book)