"When the Prophet ﷺ came to Al-Madinah, they were the worst people in weights and measures. Then Allah, Glorious is He revealed: "Woe to the Mutaffifun (those who give less in measure and weight)",[1] and they were fair in weights and measures after that. (Using translation from Ibn Mājah 2223)
لَمَّا قَدِمَ نَبِيُّ اللهِ ﷺ الْمَدِينَةَ فَكَانُوا مِنْ أَخْبَثِ النَّاسِ كَيْلًا فَأَنْزَلَ اللهُ ﷻ {وَيْلٌ لِلْمُطَفِّفِينَ} [المطففين 1] فَحَسَّنُوا الْكَيْلَ بَعْدَ ذَلِكَ