Quran 7, Al-A'raf (The Heights) ⓘ

7:85And unto Midian (We sent) their brother, Shu'eyb. He said: O my people! Serve Allah. Ye have no other Allah save Him. Lo! a clear proof hath come unto you from your Lord; so give full measure and full weight and wrong not mankind in their goods, and work not confusion in the earth after the fair ordering thereof. That will be better for you, if ye are believers.

وَإِلَى مَدْيَنَ أَخَاهُمْ شُعَيْبًا قَالَ يَا قَوْمِ اعْبُدُوا اللَّهَ مَا لَكُمْ مِنْ إِلَهٍ غَيْرُهُ قَدْ جَاءَتْكُمْ بَيِّنَةٌ مِنْ رَبِّكُمْ فَأَوْفُوا الْكَيْلَ وَالْمِيزَانَ وَلَا تَبْخَسُوا النَّاسَ أَشْيَاءَهُمْ وَلَا تُفْسِدُوا فِي الْأَرْضِ بَعْدَ إِصْلَاحِهَا ذَلِكُمْ خَيْرٌ لَكُمْ إِنْ كُنْتُمْ مُؤْمِنِينَ