Question

Why did Justinian I want to reform the law of the byzantine Empire

Answer 1

So the Emperor Justinian of the Byzantine Empire had many accomplishments. He is remembered for building Hagia Sophia, a church built during his campaign to beautiful Constantinople and restore Roman glory. "Hagia Sophia" actually means "Holy Wisdom" and Justinian said "Glory to God who has judged me worthy of accomplishing such a work as this! O Solomon, I have surpassed you!" (referring to King Solomon's temple in Jerusalem). Justinian is perhaps best remembered for his reform of the law. The result was "Corpus Juris Civilis" or "Body of Civil Law." This massive collection of laws included laws passed by Roman assemblies, Roman emperors, and included the legal writings of Roman judges and a handbook for students. Thirdly, Justinian used the law to exercise absolute power over the Byzantine empire. He had himself deemed Christ's co-ruler on Earth.
~Jess~

Answer 2

Mainly to clean it up. The Byzantine Empire inherited a lot of laws from Rome and over many years, new laws and edicts continued piling into it. Imagine a desk with important notes stacked on top of it and every time someone works there, they keep adding to the pile even if another person may have already done some of the work.

So Justinian pushed to create a clear set of laws that every court in the empire could rely on and which every person could count on for justice no matter where they were within it.