You get a greater gain from trade when the trading partners produce goods for which they each have comparative advantage.
At its simplest, the purpose Justinian had in mind was to organize the laws in the Byzantine Empire. It was a mammoth task, as you might well imagine.
In doing this, the laws were put down in writing, presumably some old laws that had outlived their usefulness were discarded, and laws were enacted that dealt with situations that were contemporary at the time or could be foreseen as necessary for future generations.
He has unlimited power and authority
he wanted to jail people who opposed his policies
