Obligatory Charity Tax (Zakat)
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.Narrated Ibn `Umar: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
From Sahih al-Bukhari, whose reports the scholars accept as authentic.