Sayyiduna Suwayd bin Qays (may Allah be pleased with him) reported: Makhrafah and I (may Allah be pleased with them both) brought cloth from Hajar or Bahrain. When we were at Mina, the Messenger of Allah (peace and blessings be upon him) bought a pair of trousers from me. He said: There was a weigher there who weighed for a wage. The Messenger of Allah (peace and blessings be upon him) gave him the price and said: "Weigh, and give good weight."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11169