Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates: (The narrator says that I think this is the statement of the Prophet Muhammad, peace and blessings be upon him) "When you make a sale by advance payment (salam), then do not sell it further until you have measured it completely."
Hadith Referenceسنن الدارقطني / كتاب البيوع / 2978
Hadith Takhrij«أخرجه الدارقطني فى ((سننه)) برقم: 2978 ، انفرد به المصنف من هذا الطريق»