(95) بَابُ مَنْ أَجْرَى أَمْرَ الأَمْصَارِ عَلَى مَا يَتَعَارَفُونَ بَيْنَهُمْ فِي الْبُيُوعِ وَالإِجَارَةِ وَالْمِكْيَالِ، وَالْوَزْنِ، وَسُنَنِهِمْ عَلَى نِيَّاتِهِمْ وَمَذَاهِبِهِمِ الْمَشْهُورَةِ
Narrated Anas bin Malik:
Abu Taiba cupped Allah's Messenger (ﷺ) and so Allah's Messenger (ﷺ) ordered that a Sa of dates be paid to him and ordered his masters (for he was a slave) to reduce his tax.
Reference: Sahih al-Bukhari 2210
In-book reference: Book 34, Hadith 156
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 34, Hadith 412