What is the ruling on studying positive law until graduation, then working in elementary education, and is repentance required for having studied it?

Man-made laws are of two types: regulatory laws that do not contradict Islamic law, such as traffic regulations. These are permissible to establish and study, and the ruler (Wali al-Amr) has the authority to enact regulations that restrict permissible matters for the public interest. Another type contradicts Islamic law, such as permitting usury. These are not permissible to enact or to seek judgment by. As for studying man-made laws that contradict Islamic law, it is permissible if the purpose is sound, such as understanding their inconsistencies, or demonstrating the virtue of Islamic law, or benefiting from aspects that do not contradict Islamic law, provided that the student is qualified to distinguish truth from falsehood.