Ibn Abi al-Shuwarab محمد بن عبد الملك بن أبي الشوارب · The Chapters on Business Transactions

"I heard Malik Abu Safwan bin 'Umairah, say: 'I bought a pair of trousers from the Messenger of Allah (ﷺ) before the Hijrah, and he weighed it for me and allowed more."'

Zaid, Abu 'Ayyash, the freed slave of Bani Zuhrah, told him that he asked Sa'd bin Abu Waqqas about buying wheat with barley. Sa'd said to him: "Which of them is better?" He said: "Wheat." He told him not to do that and said: "I heard the Messenger of Allah (ﷺ) being asked about buying fresh dates with dried dates, and he said: 'Do fresh dates decrease in weight when they become dry?' They said: 'Yes.' So he told them…