Surah Al-Isra' (The Night Journey), Verse 35

وَاَوْفُوا الْكَیْلَ اِذَا كِلْتُمْ وَزِنُوْا بِالْقِسْطَاسِ الْمُسْتَقِیْمِ ذٰلِكَ خَیْرٌ وَّاَحْسَنُ تَاْوِیْلًا ۟

Wa awful kaila izaa kiltum wa zinoo bilqistaasil mustaqeem; zaalika khairunw wa ahsanu ta'weelaa

“Give full measure when ye measure, and weigh with a balance that is straight: that is the most fitting and the most advantageous in the final determination.”

Quran 17:35 (Yusuf Ali Translation)