Sahih al-Bukhari 1486
Sahih al-Bukhari · Book 24: Obligatory Charity Tax (Zakat) · Whoever sold his fruits, trees, land or crops and gave Zakat from some other property
Narrated Ibn `Umar:
حَدَّثَنَا حَجَّاجٌ ، حَدَّثَنَا شُعْبَةُ ، أَخْبَرَنِي عَبْدُ اللَّهِ بْنُ دِينَارٍ ، سَمِعْتُ ابْنَ عُمَرَ ـ رضى الله عنهما ـ نَهَى النَّبِيُّ صلى الله عليه وسلم عَنْ بَيْعِ الثَّمَرَةِ حَتَّى يَبْدُوَ صَلاَحُهَا. وَكَانَ إِذَا سُئِلَ عَنْ صَلاَحِهَا قَالَ حَتَّى تَذْهَبَ عَاهَتُهُ.
The Prophet (ﷺ) had forbidden the sale of dates till they were good (ripe), and when it was asked what it meant, the Prophet (ﷺ) said, "Till there is no danger of blight."