One is that much has been lost and the other is that the church organized by Jesus Christ had structure, and rank, it had an orderly system of teaching and the position of deacons were an introductory calling into church service. Jesus instructed the apostles on how the church was to be organized so that his teachings may be spread throughout the world in an orderly and systematic manner. Is Named After Moses Older Brother Aaron. Moses by his authority called Aaron into priestly service. Exodus 24, Aaron held a position of prominence and leadership among the elders.
Deacons are part of the rank within many of the churches today.
As a closing thought.