As per the principles of "sanctuary cleansing" we see that the sanctuary held the sins of the people.
Sin is to disobey God. How do we know what God wants from us? How do we obey Him?
At one time Moses told us how to obey God At another time, Jesus told us how to obey God.
The purpose of this is a progressive revelation of humanity's spiritual journey towards being the perfect image of God, as God created us to be.
Moses set a certain standard a drew us closer to God Jesus then set an even higher standard and drew us even closer still.
For Moses it was sufficient, but He knew there was more ahead. For Jesus, it was also sufficient, but He knew also there was more ahead ("I have yet many things to say unto you but ye cannot bear it now" - John 16:12)
