The Prophet ﷺ said, "The standard measure is the measure of the people of Madinah, and the standard weight is the weight of the people of Makkah."
أخبرنا أحمد بن سليمان قال حدثنا أبو نعيم قال حدثنا سفيان عن حنظلة عن طاوس
عن النبي ﷺ قال المكيال مكيال أهل المدينة والوزن وزن أهل مكة
Its chain is daif. It was reported by Abu Dawud in the Book of Sales, in the chapter on the saying of the Prophet ﷺ, "The standard measure is the measure of Madinah," hadith no. 3340, from the hadith of Abu Naeem Fadl bin Dukayn, through him. It is also found in al-Kubra, hadith no. 2299. Ibn Hibban graded it sahih, hadith no. 1105, and so did Daraqutni and others. However, the hadith has a serious defect, namely Thawri's use of "an" in his transmission, 1027.