It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The (standard) measure is the measure of the people of Madinah, and the (standard) weight is the weight of the people of Makkah."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13392