Hadith
أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنْ بَيْعِ الثَّمَرِ حَتَّى يَبْدُوَ صَلاَحُهُ .
It was narrated from Salim, from his father, that:the Messenger of Allah forbade selling fruits until their condition is known
Sahih · Abu Ghuddah
Sunan an-Nasa'i 4520 ·Book 44, Hadith 72·Also available on sunnah.com·