Hadith: the Messenger of Allah (may Allah's peace and blessings be upon him) forbade the Muzābanah sale: that is to sell fruits in one's garden, if it is palm trees, for dates by dry measure; and if it is a vineyard, to sell for raisins by dry measure; and if it is any crop to sell for a dry measure of its food. He forbade all such transactions

عن عبد الله بن عمر رضي الله عنهما قال: «نهى رسول الله صلى الله عليه وسلم عن المُزَابَنَةِ: أن يبيع ثَمَرَ حَائِطِهِ إن كان نَخْلًا: بتَمْرٍ كَيْلًا، وإن كان كَرْمًا: أن يبيعه بزبيب كَيْلًا، أو كان زَرْعًا: أن يبيعه بكَيْلِ طعام، نهى عن ذلك كله».
[صحيح] - [متفق عليه]

‘Abdullāh ibn ‘Umar (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) forbade the Muzābanah sale: that is to sell fruits in one's garden, if it is palm trees, for dates by dry measure; and if it is a vineyard, to sell for raisins by dry measure; and if it is any crop to sell for a dry measure of its food. He forbade all such transactions.
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

The Prophet (may Allah's peace and blessings be upon him) forbade the Muzābanah sale, which is to sell something definite for an indefinite amount of its kinds because of the harms this transaction involves, and also because of the uncertainty of the correspondence of the two commodities, which leads to usury. Examples were given to clarify and explain it: to sell fruits in one's garden, if it is a palm garden, for dates by dry measure; and if it is a vineyard, to sell for raisins by dry measure; and if it is any crop to sell for a dry measure of the food of its kind. He forbade all such transactions because of the harm and detriment it involves.