Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) narrates from the Messenger of Allah (peace and blessings be upon him) that he (peace and blessings be upon him) forbade "al-muhaqalah (muhaqalah), al-muzabanah (muzabanah), al-mukhabarah (mukhabarah), and selling dates before they ripen." He (peace and blessings be upon him) said: "Al-ishqah is that it turns red and yellow, or is eaten from." Al-muhaqalah (muhaqalah) is that the crop is sold in exchange for a known measure of food, that is, wheat. Zayd said: I said to Ata: Did you hear Jabir mentioning this from the Messenger of Allah (peace and blessings be upon him)? He said: Yes.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10602