Sunan an-Nasa'i

It was narrated that Abu Sa'eed Al-Khudri said: "The Messenger of Allah [SAW] forbade mixing Al-Busr with dried dates, or raisins with dried dates, or raisins with Al-Busr, and he said: “Whoever among you (wants to) drink them, let him drink each one of them on its own: dried dates on their own, or Al-Busr on their own, or raisins on their own”"