He asked Saad bin Abu Waqqas about exchanging white wheat for unhusked barley.Saad asked him, "Which of the two is better?"He replied, "The white wheat."So Saad forbade him from doing that and said, "I heard the Messenger of Allah ﷺ being asked about buying dried dates in exchange for fresh dates. The Messenger of Allah ﷺ asked, 'Do fresh dates decrease in weight when they dry?'They answered, 'Yes.'So he forbade that."
أنه سأل سعد بن أبي وقاص عن البيضاء بالسلت، فقال له سعد: أيتهما أفضل؟ قال: البيضاء. فنهاه عن ذلك. وقال سعد: سمعت رسول الله ﷺ يسأل عن اشتراء التمر بالرطب، فقال رسول الله ﷺ: أينقص الرطب إذا يبس؟ فقالوا: نعم، فنهي عن ذلك.
Malik related it in his chapter on sales (22), from Abdullah bin Yazid, that Zayd Abu Ayyash informed him, and he mentioned it. Through Malik's route, it was also related by Abu Dawud (3359), Tirmidhi (1225), Nasai (4549), Ibn Majah (2264), Ahmad (1515), Ibn Hibban (4997), Hakim (2/38), and Bayhaqi (5/294), all of them through this route. Tirmidhi said, "This is a hasan sahih hadith, and the practice among the people of knowledge is in accordance with it." Ismail bin Umaya, Dahhak bin Uthman, and Usama bin Zayd all followed Malik in this. But Yahya bin Abu Kathir contradicted all of them, and through his route it was related by Abu Dawud (3360), Daraqutni (49/3), Hakim (38/2-39), and Bayhaqi (294/5), adding at the end of the hadith, "on credit."Daraqutni said, "The agreement of these four against what Yahya related indicates their precision in preserving the hadith, and among them is a leading imam and memorizer, namely Malik bin Anas." After quoting Daraqutni's statement, Bayhaqi said, "The defect identified in this report indicates the error of this wording, for Imran bin Abu Anas related it from Abu Ayyash in a manner similar to the narration of the group." The conclusion is that the mention of "on credit" in this hadith is shadhdh (anomalous).Hakim said, "This is a sahih hadith, because the leading scholars of transmission are unanimous on the standing of Malik bin Anas as an authority, and that he is precise in everything he relates of hadith, since nothing but the sahih is found in his narrations, especially in the hadith of the people of Madinah. Moreover, these leading scholars corroborated him in his narration from Abdullah bin Yazid. Bukhari and Muslim did not include it only because of what they feared regarding the obscurity of Zayd Abu Ayyash."I say, Zayd Abu Ayyash is Zayd bin Ayyash al-Madani. Daraqutni deemed him reliable, and Ibn Hibban mentioned him among the reliable narrators (311/6). Hakim's statement implies that had this defect not been present in their view, they would have included it. But the matter is not as he said, for they did not commit themselves to including everything that is sahih.As for his statement, "white wheat" (bayda), it is a type of wheat, white in color. And "sult" is another type distinct from wheat, with smaller grains than it. Some scholars said that bayda is the fresh, moist form of sult, and this fits the meaning of the hadith better, as evidenced by the fact that it was compared to fresh dates alongside dried dates, for if the two were of different kinds, the comparison would not hold.Khattabi said, "This hadith is foundational in many chapters concerning matters of riba. This is because anything edible that has moisture, and whose dryness reaches a final state, may not be sold moist for dry of the same kind, such as grapes for raisins, or raw meat for dried, cured meat, and similar cases." He also said, "Most jurists have held that selling fresh dates for dried dates is not permissible, and this is the view of Malik, Shafii, and Ahmad bin Hanbal. Abu Yusuf and Muhammad bin Hasan held the same view. From Abu Hanifa, it is reported that selling fresh dates for dried dates is permissible if done for cash, and it seems that in his interpretation, the hadith's prohibition applies to a deferred transaction rather than to a cash one."This is because fresh dates and dried dates are either two different kinds, in which case their sale is permissible even with disparity in quantity, so long as it is hand to hand, or they are a single kind, in which case their sale is permissible on condition of equal measure and being hand to hand. Under either assumption, there is nothing preventing the sale of one for the other. See al-Bina'ya (369/7-370). On this basis, they interpreted the prohibition as applying to deferred sale rather than to sale for cash.