Ubaydullah bin Musa narrates from Shayban in the same way, that the news reached the Messenger of Allah (peace and blessings be upon him), and he said: "It is not permissible to take one sa' for two sa' of dates, nor one sa' for two sa' of wheat, nor one dirham for two dirhams."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10545