Hafs bin 'Umar bin al-Harith حفص بن عمر بن الحارث · Commercial Transactions (Kitab Al-Buyu)

I and Makhrafah al-Abdi imported some garments from Hajar, and brought them to Mecca. The Messenger of Allah (ﷺ) came to us walking, and after he had bargained with us for some trousers, we sold them to him. There was a man who was weighing for payment. The Messenger of Allah (ﷺ) said to him: Weigh out and give overweight.

The Prophet (ﷺ) forbade selling animals for animals when payment was to be made at a later date.

The Messenger of Allah (ﷺ) forbade selling palm-trees till the dates began to ripen, and ears of corn till they were white and were safe from blight, forbidding it both to the buyer and to the seller.