Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
malik:31-101Mālik > Yaḥyá b. Saʿīd > Saʿīd b. al-Musayyab

Malik related to me that Yahya ibn Said heard Said ibn al- Musayyab say, "When you come to a land where they give full measure and full weight, stay there. When you come to a land where they shorten the measure and weight, then do not stay there very long."  

مالك:٣١-١٠١وَحَدَّثَنِي مَالِكٌ عَنْ يَحْيَى بْنِ سَعِيدٍ أَنَّهُ سَمِعَ سَعِيدَ بْنَ الْمُسَيَّبِ

يَقُولُ إِذَا جِئْتَ أَرْضًا يُوفُونَ الْمِكْيَالَ وَالْمِيزَانَ فَأَطِلِ الْمُقَامَ بِهَا وَإِذَا جِئْتَ أَرْضًا يُنَقِّصُونَ الْمِكْيَالَ وَالْمِيزَانَ فَأَقْلِلِ الْمُقَامَ بِهَا