Complex sentence: Firstly, the content of the laws had to be made explicit and secondly that the application of the laws had to be universal, therefore the gentile king's law could be neither arbitrary nor discriminatory against Jews.
Split into simpler sentences: Firstly, the content of the laws had to be made explicit and secondly that the application of the laws had to be universal. As such the gentile king's law could be neither arbitrary nor discriminatory against Jews.